DoEasy. Controls (Part 29): ScrollBar auxiliary control

Contents

• Concept
• Improving library classes
• Base class of the ScrollBar auxiliary control
• ScrollBarVertical and ScrollBarHorisontal controls derived from the base one
• Test
• What's next?
  

Concept

In the previous article, I announced the creation of the TrackBar control - an element that allows entering numeric values by moving the slider:

Since such an object is derived from the ScrollBar control, in the current article, I will start creating this WinForms object.

A scrollbar is used to scroll the content of the form if it goes beyond the container. Scrollbars are usually located at the bottom and to the right of the form. The horizontal one at the bottom scrolls content left and right, while the vertical one scrolls up and down.

In the current article, I will develop the ScrollBar base object and two of its descendants — ScrollBarVertical and ScrollBarHorisontal. The objects will be static, i.e. will not manage the content of the form. I will deal with this in subsequent articles. Each scrollbar object will consist of an underlay and controls located on it - two buttons (up-down for a vertical scroll bar and left-right for a horizontal one). Each object should have a capture area (ThumbArea), or a "slider" so that it is possible to shift the contents of the form by grabbing it and moving it with the mouse. The buttons with arrows also serve this purpose. All these controls are already endowed with the appropriate mouse interaction functionality. Therefore, today we will simply create these objects, and in the next article we will finalize the noted shortcomings and begin developing the interaction of scrollbars with the mouse to control the content of the form.

Scrollbars should be present for all objects that allow other controls to be attached to them, which means that they should be container objects. Initially, the scrollbar is hidden if the container content fits within it. If the content starts going beyond the container, then the scrollbar should appear, allowing a user to control the visible area of the form by shifting the attached objects within it. In the current article, I will create two scrollbars (vertical and horizontal) and make them visible for the main form to evaluate their appearance and decide on what to do with them next.

Improving library classes

When hovering over the mouse and capturing the ScrollBar control area (buttons and scroll slider), they should change their color. The color changes when hovering and capturing - a different color is set for each state.
Add them to the list of macro substitutions in \MQL5\Include\DoEasy\Defines.mqh:

#define CLR_DEF_CONTROL_PROGRESS_BAR_BACK_COLOR       (C'0xF0,0xF0,0xF0')  // ProgressBar control background color
#define CLR_DEF_CONTROL_PROGRESS_BAR_BORDER_COLOR     (C'0xBC,0xBC,0xBC')  // ProgressBar control frame color
#define CLR_DEF_CONTROL_PROGRESS_BAR_FORE_COLOR       (C'0x00,0x78,0xD7')  // ProgressBar control text color
#define CLR_DEF_CONTROL_PROGRESS_BAR_BAR_COLOR        (C'0x06,0xB0,0x25')  // ProgressBar control progress line color

#define CLR_DEF_CONTROL_SCROLL_BAR_TRACK_BACK_COLOR   (C'0xF0,0xF0,0xF0')  // ScrollBar control background color
#define CLR_DEF_CONTROL_SCROLL_BAR_TRACK_BORDER_COLOR (C'0xFF,0xFF,0xFF')  // ScrollBar control frame color
#define CLR_DEF_CONTROL_SCROLL_BAR_TRACK_FORE_COLOR   (C'0x60,0x60,0x60')  // ScrollBar control text color
#define CLR_DEF_CONTROL_SCROLL_BAR_THUMB_COLOR        (C'0xCD,0xCD,0xCD')  // ScrollBar control capture area color
#define CLR_DEF_CONTROL_SCROLL_BAR_THUMB__MOUSE_DOWN  (C'0x60,0x60,0x60')  // Color of ScrollBar control capture area when clicking on the control
#define CLR_DEF_CONTROL_SCROLL_BAR_THUMB_MOUSE_OVER   (C'0xA6,0xA6,0xA6')  // Color of ScrollBar control capture area when hovering over the control

#define DEF_CONTROL_LIST_MARGIN_X                     (1)                  // Gap between columns in ListBox controls
#define DEF_CONTROL_LIST_MARGIN_Y                     (0)                  // Gap between rows in ListBox controls

Add three new types to the list of graphical element types in the same file:

//+---------------------------------------------+
//| The list of graphical element types         |
//+---------------------------------------------+
enum ENUM_GRAPH_ELEMENT_TYPE
  {
   GRAPH_ELEMENT_TYPE_STANDARD,                       // Standard graphical object
   GRAPH_ELEMENT_TYPE_STANDARD_EXTENDED,              // Extended standard graphical object
   GRAPH_ELEMENT_TYPE_SHADOW_OBJ,                     // Shadow object
   GRAPH_ELEMENT_TYPE_ELEMENT,                        // Element
   GRAPH_ELEMENT_TYPE_FORM,                           // Form
   GRAPH_ELEMENT_TYPE_WINDOW,                         // Window
   //--- WinForms
   GRAPH_ELEMENT_TYPE_WF_UNDERLAY,                    // Panel object underlay
   GRAPH_ELEMENT_TYPE_WF_BASE,                        // Windows Forms Base
   //--- 'Container' object types are to be set below
   GRAPH_ELEMENT_TYPE_WF_CONTAINER,                   // Windows Forms container base object
   GRAPH_ELEMENT_TYPE_WF_PANEL,                       // Windows Forms Panel
   GRAPH_ELEMENT_TYPE_WF_GROUPBOX,                    // Windows Forms GroupBox
   GRAPH_ELEMENT_TYPE_WF_TAB_CONTROL,                 // Windows Forms TabControl
   GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER,             // Windows Forms SplitContainer
   //--- 'Standard control' object types are to be set below
   GRAPH_ELEMENT_TYPE_WF_COMMON_BASE,                 // Windows Forms base standard control
   GRAPH_ELEMENT_TYPE_WF_LABEL,                       // Windows Forms Label
   GRAPH_ELEMENT_TYPE_WF_BUTTON,                      // Windows Forms Button
   GRAPH_ELEMENT_TYPE_WF_CHECKBOX,                    // Windows Forms CheckBox
   GRAPH_ELEMENT_TYPE_WF_RADIOBUTTON,                 // Windows Forms RadioButton
   GRAPH_ELEMENT_TYPE_WF_ELEMENTS_LIST_BOX,           // Base list object of Windows Forms elements
   GRAPH_ELEMENT_TYPE_WF_LIST_BOX,                    // Windows Forms ListBox
   GRAPH_ELEMENT_TYPE_WF_CHECKED_LIST_BOX,            // Windows Forms CheckedListBox
   GRAPH_ELEMENT_TYPE_WF_BUTTON_LIST_BOX,             // Windows Forms ButtonListBox
   GRAPH_ELEMENT_TYPE_WF_TOOLTIP,                     // Windows Forms ToolTip
   GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR,                // Windows Forms ProgressBar
   //--- Auxiliary elements of WinForms objects
   GRAPH_ELEMENT_TYPE_WF_LIST_BOX_ITEM,               // Windows Forms ListBoxItem
   GRAPH_ELEMENT_TYPE_WF_TAB_HEADER,                  // Windows Forms TabHeader
   GRAPH_ELEMENT_TYPE_WF_TAB_FIELD,                   // Windows Forms TabField
   GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER_PANEL,       // Windows Forms SplitContainerPanel
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON,                // Windows Forms ArrowButton
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP,             // Windows Forms UpArrowButton
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN,           // Windows Forms DownArrowButton
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT,           // Windows Forms LeftArrowButton
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT,          // Windows Forms RightArrowButton
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_UD_BOX,        // Windows Forms UpDownArrowButtonsBox
   GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_LR_BOX,        // Windows Forms LeftRightArrowButtonsBox
   GRAPH_ELEMENT_TYPE_WF_SPLITTER,                    // Windows Forms Splitter
   GRAPH_ELEMENT_TYPE_WF_HINT_BASE,                   // Windows Forms HintBase
   GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_LEFT,              // Windows Forms HintMoveLeft
   GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_RIGHT,             // Windows Forms HintMoveRight
   GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_UP,                // Windows Forms HintMoveUp
   GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_DOWN,              // Windows Forms HintMoveDown
   GRAPH_ELEMENT_TYPE_WF_BAR_PROGRESS_BAR,            // Windows Forms BarProgressBar
   GRAPH_ELEMENT_TYPE_WF_GLARE_OBJ,                   // Glare object
   GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR,                  // Windows Forms ScrollBar
   GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,       // Windows Forms ScrollBarHorisontal
   GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,         // Windows Forms ScrollBarVertical
  };
//+------------------------------------------------------------------+

Here I have added one basic scrollbar element and two controls derived from it - horizontal and vertical scrollbars.

In \MQL5\Include\DoEasy\Data.mqh, add the new message indices:

   MSG_GRAPH_ELEMENT_TYPE_WF_BAR_PROGRESS_BAR,        // BarProgressBar control
   MSG_GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR,            // ProgressBar control
   MSG_GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR,              // ScrollBar control
   MSG_GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,     // ScrollBarVertical control
   MSG_GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,   // ScrollBarHorisontal control
   MSG_GRAPH_ELEMENT_TYPE_WF_GLARE_OBJ,               // Glare object

and message texts corresponding to newly added indices:

   {"Элемент управления BarProgressBar","Control element \"BarProgressBar\""},
   {"Элемент управления ProgressBar","Control element \"ProgressBar\""},
   {"Элемент управления ScrollBar","Control element \"ScrollBar\""},
   {"Элемент управления ScrollBarVertical","Control element \"ScrollBarVertical\""},
   {"Элемент управления ScrollBarHorisontal","Control element \"ScrollBarHorisontal\""},
   {"Объект блика","Glare object"},

Now we can display descriptions of new objects created here.

To display descriptions of the graphical objects of the library, use the TypeElementDescription() method in the class of the base object of all graphical objects of the library in \MQL5\Include\DoEasy\Objects\Graph\GBaseObj.mqh.

Let's add the output of the description of new objects to it:

//+------------------------------------------------------------------+
//| Return the description of the graphical element type             |
//+------------------------------------------------------------------+
string CGBaseObj::TypeElementDescription(const ENUM_GRAPH_ELEMENT_TYPE type)
  {
   return
     (
      type==GRAPH_ELEMENT_TYPE_STANDARD                  ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_STANDARD)                 :
      type==GRAPH_ELEMENT_TYPE_STANDARD_EXTENDED         ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_STANDARD_EXTENDED)        :
      type==GRAPH_ELEMENT_TYPE_ELEMENT                   ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_ELEMENT)                  :
      type==GRAPH_ELEMENT_TYPE_SHADOW_OBJ                ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_SHADOW_OBJ)               :
      type==GRAPH_ELEMENT_TYPE_FORM                      ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_FORM)                     :
      type==GRAPH_ELEMENT_TYPE_WINDOW                    ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WINDOW)                   :
      //--- WinForms
      type==GRAPH_ELEMENT_TYPE_WF_UNDERLAY               ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_UNDERLAY)              :
      type==GRAPH_ELEMENT_TYPE_WF_BASE                   ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_BASE)                  :
      //--- Containers
      type==GRAPH_ELEMENT_TYPE_WF_CONTAINER              ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_CONTAINER)             :
      type==GRAPH_ELEMENT_TYPE_WF_GROUPBOX               ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_GROUPBOX)              :
      type==GRAPH_ELEMENT_TYPE_WF_PANEL                  ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_PANEL)                 :
      type==GRAPH_ELEMENT_TYPE_WF_TAB_CONTROL            ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_TAB_CONTROL)           :
      type==GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER        ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER)       :
      //--- Standard controls
      type==GRAPH_ELEMENT_TYPE_WF_COMMON_BASE            ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_COMMON_BASE)           :
      type==GRAPH_ELEMENT_TYPE_WF_LABEL                  ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_LABEL)                 :
      type==GRAPH_ELEMENT_TYPE_WF_CHECKBOX               ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_CHECKBOX)              :
      type==GRAPH_ELEMENT_TYPE_WF_RADIOBUTTON            ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_RADIOBUTTON)           :
      type==GRAPH_ELEMENT_TYPE_WF_BUTTON                 ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_BUTTON)                :
      type==GRAPH_ELEMENT_TYPE_WF_ELEMENTS_LIST_BOX      ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ELEMENTS_LIST_BOX)     :
      type==GRAPH_ELEMENT_TYPE_WF_LIST_BOX               ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_LIST_BOX)              :
      type==GRAPH_ELEMENT_TYPE_WF_LIST_BOX_ITEM          ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_LIST_BOX_ITEM)         :
      type==GRAPH_ELEMENT_TYPE_WF_CHECKED_LIST_BOX       ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_CHECKED_LIST_BOX)      :
      type==GRAPH_ELEMENT_TYPE_WF_BUTTON_LIST_BOX        ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_BUTTON_LIST_BOX)       :
      type==GRAPH_ELEMENT_TYPE_WF_TOOLTIP                ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_TOOLTIP)               :
      type==GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR           ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR)          :
      //--- Auxiliary control objects
      type==GRAPH_ELEMENT_TYPE_WF_TAB_HEADER             ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_TAB_HEADER)            :
      type==GRAPH_ELEMENT_TYPE_WF_TAB_FIELD              ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_TAB_FIELD)             :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON           ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON)          :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP        ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP)       :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN      ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN)     :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT      ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT)     :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT     ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT)    :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_UD_BOX   ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_UD_BOX)  :
      type==GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_LR_BOX   ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_LR_BOX)  :
      type==GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER_PANEL  ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER_PANEL) :
      type==GRAPH_ELEMENT_TYPE_WF_SPLITTER               ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_SPLITTER)              :
      type==GRAPH_ELEMENT_TYPE_WF_HINT_BASE              ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_HINT_BASE)             :
      type==GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_LEFT         ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_LEFT)        :
      type==GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_RIGHT        ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_RIGHT)       :
      type==GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_UP           ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_UP)          :
      type==GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_DOWN         ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_DOWN)        :
      type==GRAPH_ELEMENT_TYPE_WF_BAR_PROGRESS_BAR       ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_BAR_PROGRESS_BAR)      :
      type==GRAPH_ELEMENT_TYPE_WF_GLARE_OBJ              ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_GLARE_OBJ)             :
      type==GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR             ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR)            :
      type==GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL    ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL)   :
      type==GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL  ? CMessage::Text(MSG_GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL) :
      "Unknown"
     );
  }  
//+------------------------------------------------------------------+

The method receives the object type. Depending on the passed type, the method returns a text string using the object of the text message class of the CMessage library I considered in the articles of the first series of the library description.

Base class of the ScrollBar auxiliary control

The base scrollbar object will be inherited from the base class of all WinForms library objects. It will be some kind of abstract scrollbar object, while the necessary parameters for a particular object will already be specified in its descendants.

In the folder of the library auxiliary objects \MQL5\Include\DoEasy\Objects\Graph\WForms\Helpers\, create the new class CScrollBar in ScrollBar.mqh. The class should be derived from the CWinFormBase class, while the files of this and other classes should be included into the file of the created object:

//+------------------------------------------------------------------+
//|                                                    ScrollBar.mqh |
//|                                  Copyright 2022, MetaQuotes Ltd. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2022, MetaQuotes Ltd."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
#property strict    // Necessary for mql4
//+---------------------------------------------+
//| Include files                               |
//+---------------------------------------------+
#include "..\WinFormBase.mqh"
#include "ArrowDownButton.mqh"
#include "ArrowUpButton.mqh"
#include "ArrowLeftButton.mqh"
#include "ArrowRightButton.mqh"
//+---------------------------------------------+
//| CScrollBar object class of WForms controls  |
//+---------------------------------------------+
class CScrollBar : public CWinFormBase
  {

In the private section of the class, declare the methods for creating arrow buttons, the standard method for creating a new graphic object, the method for calculating the size of the capture area (slider) and the method for initializing object parameters:

//+------------------------------------------------------------------+
//| CScrollBar object class of WForms controls                       |
//+------------------------------------------------------------------+
class CScrollBar : public CWinFormBase
  {
private:
//--- Create the ArrowButton objects
   virtual void      CreateArrowButtons(const int width,const int height) { return; }
//--- Create a new graphical object
   virtual CGCnvElement *CreateNewGObject(const ENUM_GRAPH_ELEMENT_TYPE type,
                                          const int element_num,
                                          const string descript,
                                          const int x,
                                          const int y,
                                          const int w,
                                          const int h,
                                          const color colour,
                                          const uchar opacity,
                                          const bool movable,
                                          const bool activity);
//--- Calculate the capture area size
   virtual int       CalculateThumbAreaSize(void);
//--- Initialize the element properties
   void              Initialize(void);

protected:

The method that calculates the size of the slider in different child objects will produce different sizes of the capture area, since its location depends on the orientation of the scroll bar - vertical or horizontal. The method for creating button objects will also create different buttons in different inherited objects: for the vertical scroll bar, we need buttons with up and down arrows, and for the horizontal scroll bar, we need buttons with left and right arrows. All of these methods are made virtual so that they can be overridden in derived classes.

In the protected section of the class, declare the virtual method for creating a capture area (the buttons and the slider will be created in the method) and the protected constructor (standard for graphical elements of the library). In the public section, write the methods that return object property maintenance flags, the parametric constructor and the virtual object timer event handler:

protected:
//--- Create the capture area object
   virtual void      CreateThumbArea(void);
//--- Protected constructor with object type, chart ID and subwindow
                     CScrollBar(const ENUM_GRAPH_ELEMENT_TYPE type,
                                CGCnvElement *main_obj,CGCnvElement *base_obj,
                                const long chart_id,
                                const int subwindow,
                                const string descript,
                                const int x,
                                const int y,
                                const int w,
                                const int h);
public:
//--- Supported object properties (1) integer, (2) real and (3) string ones
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_INTEGER property) { return true; }
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_DOUBLE property)  { return true; }
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_STRING property)  { return true; }
   
//--- Constructor
                     CScrollBar(CGCnvElement *main_obj,CGCnvElement *base_obj,
                                const long chart_id,
                                const int subwindow,
                                const string descript,
                                const int x,
                                const int y,
                                const int w,
                                const int h);
//--- Timer
   virtual void      OnTimer(void);
  };
//+------------------------------------------------------------------+

We consider similar methods every time we create a new graphical element - they are all identical and have the same purpose for each graphical object in the library.

Let's consider the implementation of the declared methods.

Protected constructor:

//+---------------------------------------------+
//| Protected constructor with an object type,  |
//| chart ID and subwindow                      |
//+---------------------------------------------+
CScrollBar::CScrollBar(const ENUM_GRAPH_ELEMENT_TYPE type,
                       CGCnvElement *main_obj,CGCnvElement *base_obj,
                       const long chart_id,
                       const int subwindow,
                       const string descript,
                       const int x,
                       const int y,
                       const int w,
                       const int h) : CWinFormBase(type,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
//--- Set the specified graphical element type for the object and assign the library object type to the current object
   this.SetTypeElement(type);
   this.m_type=OBJECT_DE_TYPE_GWF_HELPER;
   this.Initialize();
  }
//+------------------------------------------------------------------+

The constructor receives the type of a created object and other standard parameters. In the initialization string, the type of the created object is passed to the parent class constructor. In the constructor body, set the type of a graphical element, as well as the type of a library graphical object, and call the parameter initialization method.

Parametric constructor:

//+------------------------------------------------------------------+
//| Constructor indicating the main and base objects,                |
//| chart ID and subwindow                                           |
//+------------------------------------------------------------------+
CScrollBar::CScrollBar(CGCnvElement *main_obj,CGCnvElement *base_obj,
                       const long chart_id,
                       const int subwindow,
                       const string descript,
                       const int x,
                       const int y,
                       const int w,
                       const int h) : CWinFormBase(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
   this.SetTypeElement(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR);
   this.m_type=OBJECT_DE_TYPE_GWF_HELPER;
   this.Initialize();
  }
//+------------------------------------------------------------------+

Here everything is identical to the protected constructor, but the object type is hard-coded in the initialization string as ScrollBar.

The element property initialization method:

//+---------------------------------------------+
//| Initialize the element properties           |
//+---------------------------------------------+
void CScrollBar::Initialize(void)
  {
   this.SetBorderSizeAll(1);
   this.SetBorderStyle(FRAME_STYLE_SIMPLE);
   this.SetBackgroundColor(CLR_DEF_CONTROL_SCROLL_BAR_TRACK_BACK_COLOR,true);
   this.SetBorderColor(CLR_DEF_CONTROL_SCROLL_BAR_TRACK_BORDER_COLOR,true);
   this.SetForeColor(CLR_DEF_CONTROL_SCROLL_BAR_TRACK_FORE_COLOR,true);
  }
//+------------------------------------------------------------------+

Here, set the border size of the object to one pixel on each side, set the border type to "simple" and add the element background, border and text colors.

The method that creates the capture area object:

//+---------------------------------------------+
//| Create the capture area object              |
//+---------------------------------------------+
void CScrollBar::CreateThumbArea(void)
  {
   this.CreateArrowButtons(DEF_ARROW_BUTTON_SIZE,DEF_ARROW_BUTTON_SIZE);
  }
//+------------------------------------------------------------------+

The virtual method CreateArrowButtons() is called in the method to create the arrow button objects and the slider, which should be redefined in descendant objects.

The method that calculates the size of the capture area:

//+---------------------------------------------+
//| Calculate the capture area size             |
//+---------------------------------------------+
int CScrollBar::CalculateThumbAreaSize(void)
  {
   return 0;
  }
//+------------------------------------------------------------------+

Here the method returns zero and should be overridden in derived classes, since for each of the derived objects, the size and location of the slider are different.

The method creating a new graphical object:

//+---------------------------------------------+
//| Create a new graphical object               |
//+---------------------------------------------+
CGCnvElement *CScrollBar::CreateNewGObject(const ENUM_GRAPH_ELEMENT_TYPE type,
                                           const int obj_num,
                                           const string descript,
                                           const int x,
                                           const int y,
                                           const int w,
                                           const int h,
                                           const color colour,
                                           const uchar opacity,
                                           const bool movable,
                                           const bool activity)
  {
   CGCnvElement *element=NULL;
   switch(type)
     {
      case GRAPH_ELEMENT_TYPE_WF_BUTTON               :
         element=new CButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);
        break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN    :
         element=new CArrowDownButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);
        break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP      :
         element=new CArrowUpButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);
        break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT    :
         element=new CArrowLeftButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);
        break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT   :
         element=new CArrowRightButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);
        break;
      default:
        break;
     }
   if(element==NULL)
      ::Print(DFUN,CMessage::Text(MSG_LIB_SYS_FAILED_CREATE_ELM_OBJ),this.TypeElementDescription(type));
   return element;
  }
//+------------------------------------------------------------------+

The method is standard for graphical objects of the library. It allows you to create five controls: buttons with up-down arrows, right-left arrows and the button object the slider is to be based on.

Timer event handler:

//+---------------------------------------------+
//| Timer                                       |
//+---------------------------------------------+
void CScrollBar::OnTimer(void)
  {

  }
//+------------------------------------------------------------------+

At the moment, the method is empty and does nothing. I will deal with it in subsequent articles.

This object is an abstract scrollbar. It does nothing and is used to create two other objects based on it - vertical and horizontal scrollbars.

ScrollBarVertical and ScrollBarHorisontal controls derived from the base one

Let's create objects derived from the base abstract scrollbar object - vertical and horizontal ones.

In \MQL5\Include\DoEasy\Objects\Graph\WForms\Helpers\, create a new file ScrollBarVertical.mqh of the CScrollBarVertical class.
The class should be derived from the base scrollbar object, while its file, as well as some other necessary files, should be included into the created class file:

//+------------------------------------------------------------------+
//|                                            ScrollBarVertical.mqh |
//|                                  Copyright 2022, MetaQuotes Ltd. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2022, MetaQuotes Ltd."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
#property strict    // Necessary for mql4
//+---------------------------------------------+
//| Include files                               |
//+---------------------------------------------+
#include "..\Containers\Container.mqh"
#include "..\Common Controls\Button.mqh"
#include "ArrowDownButton.mqh"
#include "ArrowUpButton.mqh"
#include "ScrollBar.mqh"
//+------------------------------------------------------------------+
//| CScrollBarVertical object class of WForms controls               |
//+------------------------------------------------------------------+
class CScrollBarVertical : public CScrollBar
  {
  }

In the private section of the class, declare the virtual method for creating arrow buttons and the method for calculating the size of the capture area.
In the protected section, declare the protected class constructor, while in the public section, implement the methods that return flags for maintaining the object properties, the parametric constructor and the timer event handler:

//+------------------------------------------------------------------+
//| CScrollBarVertical object class of WForms controls               |
//+------------------------------------------------------------------+
class CScrollBarVertical : public CScrollBar
  {
private:
//--- Create the ArrowButton objects
   virtual void      CreateArrowButtons(const int width,const int height);
//--- Calculate the capture area size
   virtual int       CalculateThumbAreaSize(void);

protected:
//--- Protected constructor with object type, chart ID and subwindow
                     CScrollBarVertical(const ENUM_GRAPH_ELEMENT_TYPE type,
                                        CGCnvElement *main_obj,CGCnvElement *base_obj,
                                        const long chart_id,
                                        const int subwindow,
                                        const string descript,
                                        const int x,
                                        const int y,
                                        const int w,
                                        const int h);
public:
//--- Supported object properties (1) integer, (2) real and (3) string ones
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_INTEGER property) { return true; }
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_DOUBLE property)  { return true; }
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_STRING property)  { return true; }
   
//--- Constructor
                     CScrollBarVertical(CGCnvElement *main_obj,CGCnvElement *base_obj,
                                        const long chart_id,
                                        const int subwindow,
                                        const string descript,
                                        const int x,
                                        const int y,
                                        const int w,
                                        const int h);
//--- Timer
   virtual void      OnTimer(void);
  };
//+------------------------------------------------------------------+

Let's take a closer look at the declared methods.

Protected constructor:

//+---------------------------------------------+
//| Protected constructor with an object type,  |
//| chart ID and subwindow                      |
//+---------------------------------------------+
CScrollBarVertical::CScrollBarVertical(const ENUM_GRAPH_ELEMENT_TYPE type,
                                       CGCnvElement *main_obj,CGCnvElement *base_obj,
                                       const long chart_id,
                                       const int subwindow,
                                       const string descript,
                                       const int x,
                                       const int y,
                                       const int w,
                                       const int h) : CScrollBar(type,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
//--- Set the specified graphical element type for the object and assign the library object type to the current object
   this.SetTypeElement(type);
   this.CreateThumbArea();
  }
//+------------------------------------------------------------------+

The constructor receives the type of a created object and other parameters of its creation. The object type is passed to the parent class constructor in the initialization string. In the constructor body, set the graphical object type and call the method of creating the capture area (buttons and slider).

Parametric constructor:

//+------------------------------------------------------------------+
//| Constructor indicating the main and base objects,                |
//| chart ID and subwindow                                           |
//+------------------------------------------------------------------+
CScrollBarVertical::CScrollBarVertical(CGCnvElement *main_obj,CGCnvElement *base_obj,
                                       const long chart_id,
                                       const int subwindow,
                                       const string descript,
                                       const int x,
                                       const int y,
                                       const int w,
                                       const int h) : CScrollBar(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
   this.SetTypeElement(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL);
   this.CreateThumbArea();
  }
//+------------------------------------------------------------------+

Here everything is identical to the protected constructor discussed above, but the object type is hard-coded as the "Vertical scrollbar".

The method creating the ArrowButton objects:

//+---------------------------------------------+
//| Create the ArrowButton objects              |
//+---------------------------------------------+
void CScrollBarVertical::CreateArrowButtons(const int width,const int height)
  {
   this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP,  -1,0,                   width,height,this.BackgroundColor(),255,true,false);
   this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN,-1,this.Height()-2*height,width,height,this.BackgroundColor(),255,true,false);
   this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_BUTTON,0,this.Height()/2-height,width,height,CLR_DEF_CONTROL_SCROLL_BAR_THUMB_COLOR,255,true,false);
  }
//+------------------------------------------------------------------+

Here, create a button object with the up arrow, a button object with the down arrow and a button object, which will act as a slider.

In all these objects, the functionality of interaction with the mouse cursor has already been created. Therefore, in the next article, I will simply implement event handlers for these objects to manage the contents of the container the scrollbar is attached to.

The method that calculates the size of the capture area:

//+---------------------------------------------+
//| Calculate the capture area size             |
//+---------------------------------------------+
int CScrollBarVertical::CalculateThumbAreaSize(void)
  {
   return 0;
  }
//+------------------------------------------------------------------+

In this version of the object, the method simply returns null. The slider object is created with a fixed size, and all changes to its size will be done in subsequent articles. The size of the slider depends on the amount of content that extends beyond the container - the more data does not fit in the visible area of the form, the smaller the size of the slider. I will deal with all these calculations when creating the functionality for interaction of the mouse with the scrollbar.

Timer event handler:

//+---------------------------------------------+
//| Timer                                       |
//+---------------------------------------------+
void CScrollBarVertical::OnTimer(void)
  {

  }
//+------------------------------------------------------------------+

We will deal with the creation of the handler functionality in subsequent articles.

The horizontal scrollbar control is identical to the newly created vertical scrollbar. Let's consider the class as a whole without any explanation, since all of the above applies to the class of this object as well.

The class should be created in ScrollBarHorisontal.mqh in \MQL5\Include\DoEasy\Objects\Graph\WForms\Helpers\ScrollBarHorisontal.mqh:

//+------------------------------------------------------------------+
//|                                            ScrollBarVertical.mqh |
//|                                  Copyright 2022, MetaQuotes Ltd. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2022, MetaQuotes Ltd."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
#property strict    // Necessary for mql4
//+---------------------------------------------+
//| Include files                               |
//+---------------------------------------------+
#include "..\Containers\Container.mqh"
#include "..\Common Controls\Button.mqh"
#include "ArrowLeftButton.mqh"
#include "ArrowRightButton.mqh"
//+------------------------------------------------------------------+
//| CScrollBarHorisontal object class of WForms controls             |
//+------------------------------------------------------------------+
class CScrollBarHorisontal : public CScrollBar
  {
private:
//--- Create the ArrowButton objects
   virtual void      CreateArrowButtons(const int width,const int height);
//--- Calculate the capture area size
   virtual int       CalculateThumbAreaSize(void);

protected:
//--- Protected constructor with object type, chart ID and subwindow
                     CScrollBarHorisontal(const ENUM_GRAPH_ELEMENT_TYPE type,
                                          CGCnvElement *main_obj,CGCnvElement *base_obj,
                                          const long chart_id,
                                          const int subwindow,
                                          const string descript,
                                          const int x,
                                          const int y,
                                          const int w,
                                          const int h);
public:
//--- Supported object properties (1) integer, (2) real and (3) string ones
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_INTEGER property) { return true; }
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_DOUBLE property)  { return true; }
   virtual bool      SupportProperty(ENUM_CANV_ELEMENT_PROP_STRING property)  { return true; }
   
//--- Constructor
                     CScrollBarHorisontal(CGCnvElement *main_obj,CGCnvElement *base_obj,
                                          const long chart_id,
                                          const int subwindow,
                                          const string descript,
                                          const int x,
                                          const int y,
                                          const int w,
                                          const int h);
//--- Timer
   virtual void      OnTimer(void);
  };
//+---------------------------------------------+
//| Protected constructor with an object type,  |
//| chart ID and subwindow                      |
//+---------------------------------------------+
CScrollBarHorisontal::CScrollBarHorisontal(const ENUM_GRAPH_ELEMENT_TYPE type,
                                           CGCnvElement *main_obj,CGCnvElement *base_obj,
                                           const long chart_id,
                                           const int subwindow,
                                           const string descript,
                                           const int x,
                                           const int y,
                                           const int w,
                                           const int h) : CScrollBar(type,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
//--- Set the specified graphical element type for the object and assign the library object type to the current object
   this.SetTypeElement(type);
   this.CreateThumbArea();
  }
//+------------------------------------------------------------------+
//| Constructor indicating the main and base objects,                |
//| chart ID and subwindow                                           |
//+------------------------------------------------------------------+
CScrollBarHorisontal::CScrollBarHorisontal(CGCnvElement *main_obj,CGCnvElement *base_obj,
                                           const long chart_id,
                                           const int subwindow,
                                           const string descript,
                                           const int x,
                                           const int y,
                                           const int w,
                                           const int h) : CScrollBar(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
   this.SetTypeElement(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL);
   this.CreateThumbArea();
  }
//+---------------------------------------------+
//| Create the ArrowButton objects              |
//+---------------------------------------------+
void CScrollBarHorisontal::CreateArrowButtons(const int width,const int height)
  {
   this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT,  -1,-1,                   width,height,this.BackgroundColor(),255,true,false);
   this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT,this.Width()-2*width,-1,width,height,this.BackgroundColor(),255,true,false);
   this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_BUTTON,this.Width()/2-width,0,width,height,CLR_DEF_CONTROL_SCROLL_BAR_THUMB_COLOR,255,true,false);
  }
//+---------------------------------------------+
//| Calculate the capture area size             |
//+---------------------------------------------+
int CScrollBarHorisontal::CalculateThumbAreaSize(void)
  {
   return 0;
  }
//+---------------------------------------------+
//| Timer                                       |
//+---------------------------------------------+
void CScrollBarHorisontal::OnTimer(void)
  {

  }
//+------------------------------------------------------------------+

The scrollbar object classes written above are always created by default in each container object regardless of a user and are hidden immediately after creation. Objects will appear only if the contents of the container go beyond its limits, or in situations specified by a developer. I will display them in the program during the test.

Since objects should be present by default in container objects, their creation should be organized in the class of the container object in \MQL5\Include\DoEasy\Objects\Graph\WForms\Containers\Container.mqh.

Include the files of the newly created objects to the file of the container object. In the private section, a simply written virtual method for creating graphical objects is turned into the method declaration (I will write its implementation below - previously, its implementation was done in inherited classes). Also, declare the methods for creating vertical and horizontal scrollbars. In the protected section, declare the method for creating both scrollbars:

//+------------------------------------------------------------------+
//|                                                    Container.mqh |
//|                                  Copyright 2022, MetaQuotes Ltd. |
//|                             https://mql5.com/en/users/artmedia70 |
//+------------------------------------------------------------------+
#property copyright "Copyright 2022, MetaQuotes Ltd."
#property link      "https://mql5.com/en/users/artmedia70"
#property version   "1.00"
#property strict    // Necessary for mql4
//+---------------------------------------------+
//| Include files                               |
//+---------------------------------------------+
#include "..\WinFormBase.mqh"
#include "..\Common Controls\RadioButton.mqh"
#include "..\Common Controls\Button.mqh"
#include "..\Helpers\ScrollBarVertical.mqh"
#include "..\Helpers\ScrollBarHorisontal.mqh"
//+------------------------------------------------------------------+
//| Class of the base container object of WForms controls            |
//+------------------------------------------------------------------+
class CContainer : public CWinFormBase
  {
private:
//--- Create a new graphical object
   virtual CGCnvElement *CreateNewGObject(const ENUM_GRAPH_ELEMENT_TYPE type,
                                          const int element_num,
                                          const string descript,
                                          const int x,
                                          const int y,
                                          const int w,
                                          const int h,
                                          const color colour,
                                          const uchar opacity,
                                          const bool movable,
                                          const bool activity);// { return NULL; }

//--- Calculate Dock objects' binding coordinates
   void              CalculateCoords(CArrayObj *list);
   
//--- Create the (1) vertical and (2) horizontal ScrollBar
   CWinFormBase     *CreateScrollBarVertical(const int width);
   CWinFormBase     *CreateScrollBarHorisontal(const int width);

protected:
//--- Adjust the element size to fit its content
   bool              AutoSizeProcess(const bool redraw);
//--- Set parameters for the attached object
   void              SetObjParams(CWinFormBase *obj,const color colour);
//--- Create vertical and horizontal ScrollBar objects
   void              CreateScrollBars(const int width);

public:

In both class constructors at the very end of object creation, call the method for creating both scrollbars:

//+---------------------------------------------+
//| Protected constructor with an object type,  |
//| chart ID and subwindow                      |
//+---------------------------------------------+
CContainer::CContainer(const ENUM_GRAPH_ELEMENT_TYPE type,
                       CGCnvElement *main_obj,CGCnvElement *base_obj,
                       const long chart_id,
                       const int subwindow,
                       const string descript,
                       const int x,
                       const int y,
                       const int w,
                       const int h) : CWinFormBase(type,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
//--- Set the specified graphical element type for the object and assign the library object type to the current object
   this.SetTypeElement(type);
   this.m_type=OBJECT_DE_TYPE_GWF_CONTAINER;
   this.SetForeColor(CLR_DEF_FORE_COLOR,true);
   this.SetFontBoldType(FW_TYPE_NORMAL);
   this.SetMarginAll(3);
   this.SetPaddingAll(0);
   this.SetDockMode(CANV_ELEMENT_DOCK_MODE_NONE,false);
   this.SetBorderStyle(FRAME_STYLE_NONE);
   this.SetAutoScroll(false,false);
   this.SetAutoScrollMarginAll(0);
   this.SetAutoSize(false,false);
   this.SetAutoSizeMode(CANV_ELEMENT_AUTO_SIZE_MODE_GROW,false);
   this.Initialize();
   this.SetCoordXInit(x);
   this.SetCoordYInit(y);
   this.SetWidthInit(w);
   this.SetHeightInit(h);
   this.CreateScrollBars(10);
  }
//+------------------------------------------------------------------+
//| Constructor indicating the main and base objects,                |
//| chart ID and subwindow                                           |
//+------------------------------------------------------------------+
CContainer::CContainer(CGCnvElement *main_obj,CGCnvElement *base_obj,
                       const long chart_id,
                       const int subwindow,
                       const string descript,
                       const int x,
                       const int y,
                       const int w,
                       const int h) : CWinFormBase(GRAPH_ELEMENT_TYPE_WF_CONTAINER,main_obj,base_obj,chart_id,subwindow,descript,x,y,w,h)
  {
   this.SetTypeElement(GRAPH_ELEMENT_TYPE_WF_CONTAINER);
   this.m_type=OBJECT_DE_TYPE_GWF_CONTAINER;
   this.SetForeColor(CLR_DEF_FORE_COLOR,true);
   this.SetFontBoldType(FW_TYPE_NORMAL);
   this.SetMarginAll(3);
   this.SetPaddingAll(0);
   this.SetDockMode(CANV_ELEMENT_DOCK_MODE_NONE,false);
   this.SetBorderStyle(FRAME_STYLE_NONE);
   this.SetAutoScroll(false,false);
   this.SetAutoScrollMarginAll(0);
   this.SetAutoSize(false,false);
   this.SetAutoSizeMode(CANV_ELEMENT_AUTO_SIZE_MODE_GROW,false);
   this.Initialize();
   this.SetCoordXInit(x);
   this.SetCoordYInit(y);
   this.SetWidthInit(w);
   this.SetHeightInit(h);
   this.CreateScrollBars(10);
  }
//+------------------------------------------------------------------+

After the container object is created, two scrollbars will be attached to it. Once created, the bars will be hidden.

In the method that sets parameters to the attached object, write a code block, where the properties of the newly created scrollbar objects are set:

//+---------------------------------------------+
//| Set parameters for the attached object      |
//+---------------------------------------------+
void CContainer::SetObjParams(CWinFormBase *obj,const color colour)
  {
//--- Set the text color of the object to be the same as that of the base container
   obj.SetForeColor(this.ForeColor(),true);
//--- If the created object is not a container, set the same group for it as the one for its base object
   if(obj.TypeGraphElement()<GRAPH_ELEMENT_TYPE_WF_CONTAINER || obj.TypeGraphElement()>GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER)
      obj.SetGroup(this.Group());
//--- Depending on the object type
   switch(obj.TypeGraphElement())
     {
      //--- For the Container, Panel and GroupBox WinForms objects
      case GRAPH_ELEMENT_TYPE_WF_CONTAINER            :
      case GRAPH_ELEMENT_TYPE_WF_PANEL                :
      case GRAPH_ELEMENT_TYPE_WF_GROUPBOX             :
        obj.SetBorderColor(obj.BackgroundColor(),true);
        break;
      //--- For "Label", "CheckBox" and "RadioButton" WinForms objects
      case GRAPH_ELEMENT_TYPE_WF_LABEL                :
      case GRAPH_ELEMENT_TYPE_WF_CHECKBOX             :
      case GRAPH_ELEMENT_TYPE_WF_RADIOBUTTON          :
        obj.SetForeColor(colour==clrNONE ? this.ForeColor() : colour,true);
        obj.SetBorderColor(obj.ForeColor(),true);
        obj.SetBackgroundColor(CLR_CANV_NULL,true);
        obj.SetOpacity(0,false);
        break;
      //--- For "Button", "TabHeader", TabField and "ListBoxItem" WinForms objects
      case GRAPH_ELEMENT_TYPE_WF_BUTTON               :
      case GRAPH_ELEMENT_TYPE_WF_TAB_HEADER           :
      case GRAPH_ELEMENT_TYPE_WF_TAB_FIELD            :
      case GRAPH_ELEMENT_TYPE_WF_LIST_BOX_ITEM        :
        obj.SetForeColor(this.ForeColor(),true);
        obj.SetBackgroundColor(colour==clrNONE ? CLR_DEF_CONTROL_STD_BACK_COLOR : colour,true);
        obj.SetBorderColor(obj.ForeColor(),true);
        obj.SetBorderStyle(FRAME_STYLE_SIMPLE);
        break;
      //--- For "ListBox", "CheckedListBox" and "ButtonListBox" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_LIST_BOX             :
      case GRAPH_ELEMENT_TYPE_WF_CHECKED_LIST_BOX     :
      case GRAPH_ELEMENT_TYPE_WF_BUTTON_LIST_BOX      :
        obj.SetBackgroundColor(colour==clrNONE ? CLR_DEF_CONTROL_STD_BACK_COLOR : colour,true);
        obj.SetBorderColor(CLR_DEF_BORDER_COLOR,true);
        obj.SetForeColor(CLR_DEF_FORE_COLOR,true);
        break;
      //--- For "TabControl" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_TAB_CONTROL          :
        obj.SetBackgroundColor(colour==clrNONE ? CLR_DEF_CONTROL_TAB_BACK_COLOR : colour,true);
        obj.SetBorderColor(CLR_DEF_CONTROL_TAB_BORDER_COLOR,true);
        obj.SetForeColor(CLR_DEF_FORE_COLOR,true);
        obj.SetOpacity(CLR_DEF_CONTROL_TAB_OPACITY);
        break;
      //--- For "SplitContainer" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER      :
        obj.SetBackgroundColor(colour==clrNONE ? CLR_CANV_NULL : colour,true);
        obj.SetBorderColor(CLR_CANV_NULL,true);
        obj.SetForeColor(CLR_DEF_FORE_COLOR,true);
        obj.SetOpacity(0);
        break;
      //--- For "SplitContainerPanel" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER_PANEL:
        obj.SetBackgroundColor(colour==clrNONE ? CLR_DEF_CONTROL_SPLIT_CONTAINER_BACK_COLOR : colour,true);
        obj.SetBorderColor(CLR_DEF_CONTROL_SPLIT_CONTAINER_BORDER_COLOR,true);
        obj.SetForeColor(CLR_DEF_FORE_COLOR,true);
        break;
      //--- For "Splitter" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_SPLITTER             :
        obj.SetBackgroundColor(colour==clrNONE ? CLR_CANV_NULL : colour,true);
        obj.SetBorderColor(CLR_CANV_NULL,true);
        obj.SetForeColor(CLR_DEF_FORE_COLOR,true);
        obj.SetOpacity(0);
        obj.SetDisplayed(false);
        obj.Hide();
        break;
      //--- For the "ArrowButton" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON         :
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP      :
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN    :
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT    :
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT   :
        obj.SetBorderColor(CLR_DEF_CONTROL_TAB_HEAD_BORDER_COLOR,true);
        obj.SetBorderStyle(FRAME_STYLE_SIMPLE);
        break;
      //--- For "Hint" WinForms object
      case GRAPH_ELEMENT_TYPE_WF_HINT_BASE            :
        obj.SetBackgroundColor(CLR_CANV_NULL,true);
        obj.SetBorderColor(CLR_CANV_NULL,true);
        obj.SetForeColor(CLR_CANV_NULL,true);
        obj.SetOpacity(0,false);
        obj.SetBorderStyle(FRAME_STYLE_NONE);
        break;
      //--- For "HintMoveLeft", "HintMoveRight", "HintMoveUp" and "HintMoveDown" WinForms object 
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_LEFT       :
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_RIGHT      :
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_UP         :
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_DOWN       :
        obj.SetBackgroundColor(CLR_CANV_NULL,true);
        obj.SetBorderColor(CLR_CANV_NULL,true);
        obj.SetForeColor(CLR_DEF_CONTROL_HINT_FORE_COLOR,true);
        obj.SetOpacity(0,false);
        obj.SetBorderStyle(FRAME_STYLE_NONE);
        break;
      //--- For ToolTip WinForms object
      case GRAPH_ELEMENT_TYPE_WF_TOOLTIP              :
        obj.SetBackgroundColor(CLR_DEF_CONTROL_HINT_BACK_COLOR,true);
        obj.SetBorderColor(CLR_DEF_CONTROL_HINT_BORDER_COLOR,true);
        obj.SetForeColor(CLR_DEF_CONTROL_HINT_FORE_COLOR,true);
        obj.SetBorderStyle(FRAME_STYLE_SIMPLE);
        obj.SetOpacity(0,false);
        obj.SetDisplayed(false);
        obj.Hide();
        break;
      //--- For BarProgressBar WinForms object
      case GRAPH_ELEMENT_TYPE_WF_BAR_PROGRESS_BAR     :
        obj.SetBackgroundColor(CLR_DEF_CONTROL_PROGRESS_BAR_BAR_COLOR,true);
        obj.SetBorderColor(CLR_DEF_CONTROL_PROGRESS_BAR_BAR_COLOR,true);
        obj.SetForeColor(CLR_DEF_CONTROL_PROGRESS_BAR_FORE_COLOR,true);
        obj.SetBorderStyle(FRAME_STYLE_NONE);
        break;
      //--- For ProgressBar WinForms object
      case GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR         :
        obj.SetBackgroundColor(CLR_DEF_CONTROL_PROGRESS_BAR_BACK_COLOR,true);
        obj.SetBorderColor(CLR_DEF_CONTROL_PROGRESS_BAR_BORDER_COLOR,true);
        obj.SetForeColor(CLR_DEF_CONTROL_PROGRESS_BAR_FORE_COLOR,true);
        obj.SetBorderStyle(FRAME_STYLE_SIMPLE);
        break;
      //--- For ScrollBar WinForms object
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR           :
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL:
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL  :
        obj.SetBackgroundColor(CLR_DEF_CONTROL_SCROLL_BAR_TRACK_BACK_COLOR,true);
        obj.SetBorderColor(CLR_DEF_CONTROL_SCROLL_BAR_TRACK_BORDER_COLOR,true);
        obj.SetForeColor(CLR_DEF_CONTROL_SCROLL_BAR_TRACK_FORE_COLOR,true);
        obj.SetBorderSizeAll(1);
        obj.SetBorderStyle(FRAME_STYLE_SIMPLE);
        break;
      //--- For GlareObj WinForms object
      case GRAPH_ELEMENT_TYPE_WF_GLARE_OBJ            :
        obj.SetBackgroundColor(CLR_CANV_NULL,true);
        obj.SetBorderColor(CLR_CANV_NULL,true);
        obj.SetForeColor(CLR_CANV_NULL,true);
        obj.SetBorderStyle(FRAME_STYLE_NONE);
        break;
      default:
        break;
     }
   obj.Crop();
  }
//+------------------------------------------------------------------+

The method is always called after an object attached to the container is created. The method specifies the default parameters for the newly created object. later, they can be replaced with others. But, once created, they are always set automatically in this method.

The method creating vertical and horizontal ScrollBar objects:

//+------------------------------------------------------------------+
//| Create vertical and horizontal ScrollBar objects                 |
//+------------------------------------------------------------------+
void CContainer::CreateScrollBars(const int width)
  {
//--- Create the vertical scrollbar object
   CScrollBarVertical *sbv=this.CreateScrollBarVertical(DEF_ARROW_BUTTON_SIZE);
//--- If the object has been created
   if(sbv!=NULL)
     {
      //--- set the object non-display flag and hide it
      sbv.SetDisplayed(false);
      sbv.Hide();
     }
//--- Create the horizontal scrollbar object
   CScrollBarHorisontal *sbh=this.CreateScrollBarHorisontal(DEF_ARROW_BUTTON_SIZE);
//--- If the object has been created
   if(sbh!=NULL)
     {
      //--- set the object non-display flag and hide it
      sbh.SetDisplayed(false);
      sbh.Hide();
     }
  }
//+------------------------------------------------------------------+

The logic of the method is commented in the code. Here we simply create two scrollbars and hide them by setting them to not show flags when updating, showing and redrawing the underlying object they are attached to. In other words, scrollbars can be displayed only by explicitly allowing to display them in the program or library code in the future.

The method that creates the vertical ScrollBar:

//+---------------------------------------------+
//| Create the vertical ScrollBar               |
//+---------------------------------------------+
CWinFormBase *CContainer::CreateScrollBarVertical(const int width)
  {
//--- If failed to create the vertical scroll bar object, return NULL
   if(!this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,this.RightEdge()-width,0,width,this.HeightWorkspace(),this.BackgroundColor(),255,true,false))
      .return NULL;
//--- Return the pointer to the vertical scrollbar object
   return this.GetElementByType(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,0);
  }
//+------------------------------------------------------------------+

Create an object and return the pointer to it from the list of attached objects.

The method that creates the horizontal ScrollBar:

//+---------------------------------------------+
//| Create the horizontal ScrollBar             |
//+---------------------------------------------+
CWinFormBase *CContainer::CreateScrollBarHorisontal(const int width)
  {
//--- If failed to create the horizontal scroll bar object, return NULL
   if(!this.CreateNewElement(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,0,this.BottomEdge()-width,this.WidthWorkspace(),width,this.BackgroundColor(),255,true,false))
      .return NULL;
//--- Return the pointer to the horizontal scrollbar object
   return this.GetElementByType(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,0);
  }
//+------------------------------------------------------------------+

Create an object and return the pointer to it from the list of attached objects.

The method creating a new graphical object:

//+---------------------------------------------+
//| Create a new graphical object               |
//+---------------------------------------------+
CGCnvElement *CContainer::CreateNewGObject(const ENUM_GRAPH_ELEMENT_TYPE type,
                                           const int obj_num,
                                           const string descript,
                                           const int x,
                                           const int y,
                                           const int w,
                                           const int h,
                                           const color colour,
                                           const uchar opacity,
                                           const bool movable,
                                           const bool activity)
  {
   CGCnvElement *element=NULL;
   switch(type)
     {
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR           : element=new CScrollBar(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);          break;
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL  : element=new CScrollBarVertical(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);  break;
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL: element=new CScrollBarHorisontal(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);break;
      default  : break;
     }
   if(element==NULL)
      ::Print(DFUN,CMessage::Text(MSG_LIB_SYS_FAILED_CREATE_ELM_OBJ),this.TypeElementDescription(type));
   return element;
  }
//+------------------------------------------------------------------+

Previously, the method did nothing and was overridden in derived classes. Now it allows creating scrollbar objects.

Since the scrollbars are attached to the container objects on their bottom and right sides, resizing the form should also change the scrollbar objects. Let's do it in \MQL5\Include\DoEasy\Objects\Graph\WForms\WinFormBase.mqh of the base WinForms object.

In the method that sets the new dimensions for the current object, add the following code block:

//+---------------------------------------------+
//| Set the new size for the current object     |
//+---------------------------------------------+
bool CWinFormBase::Resize(const int w,const int h,const bool redraw)
  {
//--- If the object width and height are equal to the passed ones, return 'true'
   if(this.Width()==w && this.Height()==h)
      return true;
//--- Declare the variable with the property change result
   bool res=true;
//--- Save the panel initial size
   int prev_w=this.Width();
   int prev_h=this.Height();
//--- Set the property change result to the 'res' variable
//--- (if the property value is not equal to the passed value)
   if(this.Width()!=w)
      res &=this.SetWidth(w);
   if(this.Height()!=h)
      res &=this.SetHeight(h);
   if(!res)
      return false;
//--- Get the vertical scrollbar and
   CWinFormBase *scroll_v=this.GetElementByType(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,0);
   if(scroll_v!=NULL)
     {
      //--- change the vertical size to the size of the container workspace
      scroll_v.Resize(scroll_v.Width(),this.Height()-this.BorderSizeTop()-this.BorderSizeBottom(),false);
      //--- Get a button object with the down arrow from the vertical scrollbar object
      CWinFormBase *arr_d=scroll_v.GetElementByType(GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN,0);
      //--- If the button has been received
      if(arr_d!=NULL)
        {
         //--- Move it to the bottom edge of the vertical scrollbar
         if(arr_d.Move(arr_d.CoordX(),scroll_v.BottomEdge()-2*arr_d.Height()))
           {
            arr_d.SetCoordXRelative(arr_d.CoordX()-scroll_v.CoordX());
            arr_d.SetCoordYRelative(arr_d.CoordY()-scroll_v.CoordY());
           }
        }
     }
//--- Get the horizontal scrollbar and
   CWinFormBase *scroll_h=this.GetElementByType(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,0);
   if(scroll_h!=NULL)
     {
      //--- change the horizontal size to the size of the container workspace
      scroll_h.Resize(this.Width()-this.BorderSizeLeft()-this.BorderSizeRight(),scroll_h.Height(),false);
      //--- Get a button object with the right arrow from the horizontal scrollbar object
      CWinFormBase *arr_r=scroll_h.GetElementByType(GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT,0);
      //--- If the button has been received
      if(arr_r!=NULL)
        {
         //--- Move it to the right edge of the horizontal scrollbar
         if(arr_r.Move(scroll_h.RightEdge()-2*arr_r.Width(),arr_r.CoordY()))
           {
            arr_r.SetCoordXRelative(arr_r.CoordX()-scroll_h.CoordX());
            arr_r.SetCoordYRelative(arr_r.CoordY()-scroll_h.CoordY());
           }
        }
     }
//--- Calculate the value, by which the size should be changed
   int excess_w=this.Width()-prev_w;
   int excess_h=this.Height()-prev_h;
//--- Get the "Shadow" object
   CShadowObj *shadow=this.GetShadowObj();
//--- If the object has a shadow and the "Shadow" object has been received,
   if(this.IsShadow() && shadow!=NULL)
     {
      //--- save shadow shifts by X and Y,
      int x=shadow.CoordXRelative();
      int y=shadow.CoordYRelative();
      //--- set the shadow new width and height
      res &=shadow.SetWidth(shadow.Width()+excess_w);
      res &=shadow.SetHeight(shadow.Height()+excess_h);
      //--- If the res variable contains 'false',
      //--- there was a resize error - return 'false'
      if(!res)
         return false;
      //--- If there is no need to redraw, remove the shadow
      if(!redraw)
         shadow.Erase();
      //--- Save the previously set shadow shift values relative to the panel
      shadow.SetCoordXRelative(x);
      shadow.SetCoordYRelative(y);
     }
//--- Redraw the entire element with new size
   if(redraw)
      this.Redraw(true);
//--- All is successful - return 'true'
   return true;
  }
//+------------------------------------------------------------------+

Now, when the object is resized, the scrollbars also change accordingly. The logic of the added code block is fully described in the comments.

We include all files of all created graphical elements to the library in the class file of the panel object.

In \MQL5\Include\DoEasy\Objects\Graph\WForms\Containers\Panel.mqh, include the files of new controls:

//+---------------------------------------------+
//| Include files                               |
//+---------------------------------------------+
#include "Container.mqh"
#include "..\Helpers\TabField.mqh"
#include "..\Helpers\ArrowUpButton.mqh"
#include "..\Helpers\ArrowDownButton.mqh"
#include "..\Helpers\ArrowLeftButton.mqh"
#include "..\Helpers\ArrowRightButton.mqh"
#include "..\Helpers\ArrowUpDownBox.mqh"
#include "..\Helpers\ArrowLeftRightBox.mqh"
#include "..\Helpers\HintMoveLeft.mqh"
#include "..\Helpers\HintMoveRight.mqh"
#include "..\Helpers\HintMoveUp.mqh"
#include "..\Helpers\HintMoveDown.mqh"
#include "..\Helpers\ScrollBarVertical.mqh"
#include "..\Helpers\ScrollBarHorisontal.mqh"
#include "GroupBox.mqh"
#include "TabControl.mqh"
#include "SplitContainer.mqh"
#include "..\..\WForms\Common Controls\ListBox.mqh"
#include "..\..\WForms\Common Controls\CheckedListBox.mqh"
#include "..\..\WForms\Common Controls\ButtonListBox.mqh"
#include "..\..\WForms\Common Controls\ToolTip.mqh"
#include "..\..\WForms\Common Controls\ProgressBar.mqh"
#include "..\..\WForms\GlareObj.mqh"
//+---------------------------------------------+
//| Panel object class of WForms controls       |
//+---------------------------------------------+
class CPanel : public CContainer

In the method creating a new graphical object, add the strings for creating new scrollbar objects:

//+---------------------------------------------+
//| Create a new graphical object               |
//+---------------------------------------------+
CGCnvElement *CPanel::CreateNewGObject(const ENUM_GRAPH_ELEMENT_TYPE type,
                                       const int obj_num,
                                       const string descript,
                                       const int x,
                                       const int y,
                                       const int w,
                                       const int h,
                                       const color colour,
                                       const uchar opacity,
                                       const bool movable,
                                       const bool activity)
  {
   CGCnvElement *element=NULL;
   switch(type)
     {
      case GRAPH_ELEMENT_TYPE_ELEMENT                 : element=new CGCnvElement(type,this.GetMain(),this.GetObject(),this.ID(),obj_num,this.ChartID(),this.SubWindow(),descript,x,y,w,h,colour,opacity,movable,activity); break;
      case GRAPH_ELEMENT_TYPE_FORM                    : element=new CForm(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);               break;
      case GRAPH_ELEMENT_TYPE_WF_CONTAINER            : element=new CContainer(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);          break;
      case GRAPH_ELEMENT_TYPE_WF_GROUPBOX             : element=new CGroupBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);           break;
      case GRAPH_ELEMENT_TYPE_WF_PANEL                : element=new CPanel(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);              break;
      case GRAPH_ELEMENT_TYPE_WF_LABEL                : element=new CLabel(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);              break;
      case GRAPH_ELEMENT_TYPE_WF_CHECKBOX             : element=new CCheckBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);           break;
      case GRAPH_ELEMENT_TYPE_WF_RADIOBUTTON          : element=new CRadioButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);        break;
      case GRAPH_ELEMENT_TYPE_WF_BUTTON               : element=new CButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);             break;
      case GRAPH_ELEMENT_TYPE_WF_LIST_BOX             : element=new CListBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);            break;
      case GRAPH_ELEMENT_TYPE_WF_LIST_BOX_ITEM        : element=new CListBoxItem(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);        break;
      case GRAPH_ELEMENT_TYPE_WF_CHECKED_LIST_BOX     : element=new CCheckedListBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);     break;
      case GRAPH_ELEMENT_TYPE_WF_BUTTON_LIST_BOX      : element=new CButtonListBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);      break;
      case GRAPH_ELEMENT_TYPE_WF_TAB_HEADER           : element=new CTabHeader(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);          break;
      case GRAPH_ELEMENT_TYPE_WF_TAB_FIELD            : element=new CTabField(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);           break;
      case GRAPH_ELEMENT_TYPE_WF_TAB_CONTROL          : element=new CTabControl(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);         break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON         : element=new CArrowButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);        break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_UP      : element=new CArrowUpButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);      break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_DOWN    : element=new CArrowDownButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);    break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_LEFT    : element=new CArrowLeftButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);    break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTON_RIGHT   : element=new CArrowRightButton(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);   break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_UD_BOX : element=new CArrowUpDownBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);     break;
      case GRAPH_ELEMENT_TYPE_WF_ARROW_BUTTONS_LR_BOX : element=new CArrowLeftRightBox(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);  break;
      case GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER      : element=new CSplitContainer(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);     break;
      case GRAPH_ELEMENT_TYPE_WF_SPLITTER             : element=new CSplitter(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);           break;
      case GRAPH_ELEMENT_TYPE_WF_HINT_BASE            : element=new CHintBase(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);           break;
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_LEFT       : element=new CHintMoveLeft(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);       break;
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_RIGHT      : element=new CHintMoveRight(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);      break;
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_UP         : element=new CHintMoveUp(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);         break;
      case GRAPH_ELEMENT_TYPE_WF_HINT_MOVE_DOWN       : element=new CHintMoveDown(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);       break;
      case GRAPH_ELEMENT_TYPE_WF_TOOLTIP              : element=new CToolTip(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);            break;
      case GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR         : element=new CProgressBar(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);        break;
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR           : element=new CScrollBar(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);          break;
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL  : element=new CScrollBarVertical(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);  break;
      case GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL: element=new CScrollBarHorisontal(this.GetMain(),this.GetObject(),this.ChartID(),this.SubWindow(),descript,x,y,w,h);break;
      default  : break;
     }
   if(element==NULL)
      ::Print(DFUN,CMessage::Text(MSG_LIB_SYS_FAILED_CREATE_ELM_OBJ),this.TypeElementDescription(type));
   return element;
  }
//+------------------------------------------------------------------+

Now in this object we will be able to create scrollbar objects attached to it.

The same strings should be added to the same methods in other classes of container objects.

These changes have already been made to the library files:

SplitContainerPanel.mqh, Containers\TabControl.mqh, TabField.mqh, SplitContainer.mqh.

Let's check the result.

Test

To perform the test, I will use the EA from the previous article and save it in \MQL5\Experts\TestDoEasy\Part129\ as TestDoEasy129.mq5.

In the OnInit() handler, namely in the code block for redrawing all created objects, add getting the pointers to both scrollbars of the main panel object and forcing them to be displayed to see in what form they are created:

//--- Display and redraw all created panels
   for(int i=0;i<FORMS_TOTAL;i++)
     {
      //--- Get the panel object
      pnl=engine.GetWFPanel("WinForms Panel"+(string)i);
      if(pnl!=NULL)
        {
         //--- display and redraw the panel
         pnl.Show();
         pnl.Redraw(true);
         //--- Get the pointer to the vertical scrollbar object of the main panel
         CScrollBarVertical *sbv=pnl.GetElementByType(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_VERTICAL,0);
         //--- Set the display flag for the object and show the scrollbar
         sbv.SetDisplayed(true);
         sbv.Show();
         sbv.Redraw(true);
         //--- Get the pointer to the horizontal scrollbar object of the main panel
         CScrollBarHorisontal *sbh=pnl.GetElementByType(GRAPH_ELEMENT_TYPE_WF_SCROLL_BAR_HORISONTAL,0);
         //--- Set the display flag for the object and show the scrollbar
         sbh.SetDisplayed(true);
         sbh.Show();
         sbh.Redraw(true);
         //--- Get the TabControl object from the panel
         CTabControl *tc=pnl.GetElementByType(GRAPH_ELEMENT_TYPE_WF_TAB_CONTROL,0);
         //--- Get the SplitContainer object from the first tab of the TabControl object
         CSplitContainer *sc=tc.GetTabElementByType(0,GRAPH_ELEMENT_TYPE_WF_SPLIT_CONTAINER,0);
         //--- Get the second panel from the SplitContainer object
         CSplitContainerPanel *scp=sc.GetPanel(1);
         //--- Get the ProgressBar object from the received panel
         CProgressBar *pb=scp.GetElementByType(GRAPH_ELEMENT_TYPE_WF_PROGRESS_BAR,0);
         //--- Wait for 1/10 of a second
         Sleep(100);
         //--- Get the width of the ProgressBar object
         int w=pb.Width();
         //--- In the loop, increase the width of the ProgressBar by 180 pixels with a delay of 1/50
         for(int n=0;n<180;n++)
           {
            Sleep(20);
            pb.Resize(w+n,pb.Height(),true);
           }
         //--- Set the values for PerformStep of the ProgressBar object
         pb.SetValuesForProcessing(0,350,1,0);
         //--- Reset ProgressBar to minimum
         pb.ResetProgressBar();
         //--- If the style of the progress bar is "Continuous line", display the progress bar description
         if(pb.Style()==CANV_ELEMENT_PROGRESS_BAR_STYLE_CONTINUOUS)
            pb.ShowBarDescription();
         //--- Wait for 1/5 second
         Sleep(200);
         //--- If the style of the progress bar is not "Continuous scrolling"
         if(pb.Style()!=CANV_ELEMENT_PROGRESS_BAR_STYLE_MARQUEE)
           {
            //--- In the loop from the minimum to the maximum value of ProgressBar
            for(int n=0;n<=pb.Maximum();n++)
              {
               //--- call the method for increasing the progress bar by a given step with a wait of 1/5 second
               pb.PerformStep();
               //--- Set the number of completed steps in the description of the progress bar
               pb.SetBarDescriptionText("Progress Bar, pass: "+(InpProgressBarPercent ? pb.ValuePercentDescription() : pb.ValueDescription()));
               Sleep(20);
              }
           }
         //--- Wait for 1/2 second, set the description font type to Bold and write a completion message on the progress bar
         Sleep(500);
         pb.SetBarDescriptionFontFlags(FW_BOLD);
         pb.SetBarDescriptionText("Progress Bar: Done");
         //--- Set the glare object type - rectangle, opacity 40, color - white
         pb.SetGlareStyle(CANV_ELEMENT_VISUAL_EFF_STYLE_RECTANGLE);
         pb.SetGlareOpacity(40);
         pb.SetGlareColor(clrWhite);
        }
     }

Compile the EA and launch it on the chart:

We see that the scrollbars are created in the right places and have normal controls that respond to mouse interaction. Control objects on scrollbars are painted in the wrong colors when hovering over them with the mouse cursor because I have not created event handlers for these controls yet. I will fix this in subsequent articles.

What's next?

In the next article, I will continue the development of the ScrollBar object.

Back to contents

*Previous articles within the series:

 
DoEasy. Controls (Part 26): Finalizing the ToolTip WinForms object and moving on to ProgressBar development
DoEasy. Controls (Part 27): Working on ProgressBar WinForms object
DoEasy. Controls (Part 28): Bar styles in the ProgressBar control