Discussing the article: "The View and Controller components for tables in the MQL5 MVC paradigm: Containers"

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Check out the new article: The View and Controller components for tables in the MQL5 MVC paradigm: Containers.

In this article, we will discuss creating a "Container" control that supports scrolling its contents. Within the process, the already implemented classes of graphics library controls will be improved.

As part of the development of TableView control in MVC (Model-View-Controller) paradigm, we have already created Model component - a table model and started creating the View and Controller components. In the last article, simple but quite functional controls were created. Complex controls will be assembled from such elements. Today we will write such control classes as Panel, GroupBox and Container — all three elements are containers for placing various controls on them.

  • The Panel control is a panel that enables to place any number of other controls on it. When moving the panel to new coordinates, all the controls located on it also move along with the panel. Thus, the panel is a container for the controls located on it. However, this element does not have scrollbars that allow for scrolling through container contents if it goes beyond the panel boundaries. Such content is simply clipped to the container boundaries.
  • GroupBox control is a set of elements organized into one group. It is inherited from the panel and enables to group up elements according to some common purpose, for example, a group of RadioButton elements, where only one element from the entire group can be selected, and the rest of the group elements are deselected.
  • The Container control. Allows attaching only one control to yourself. If the attached element extends beyond the container, scrollbars appear at the container. They enable to scroll through the contents of the container. To place any number of controls in a container, it is necessary to place a panel in it, and attach the required number of controls to the panel. Thus, the container will scroll through the panel, and the latter will shift its contents after scrolling.

Thus, in addition to the three specified main controls, we have to create classes for creating scrollbars — the thumb class (Thumb) and the scrollbar class (ScrollBar). There will be two such classes — for vertical and horizontal scrollbars.

Compile the indicator and run it on the chart:


Shifting to full screen when clicking on a track works, shifting when clicking on buttons works, event auto-repeat when holding buttons works, wheel scrolling works.


Author: Artyom Trishkin

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