MQL4 and MQL5 Programming Articles

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Study the MQL5 language for programming trading strategies in numerous published articles mostly written by you - the community members. The articles are grouped into categories to help you quicker find answers to any questions related to programming: Integration, Tester, Trading Strategies, etc.

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Timeseries in DoEasy library (part 40): Library-based indicators - updating data in real time

Timeseries in DoEasy library (part 40): Library-based indicators - updating data in real time

The article considers the development of a simple multi-period indicator based on the DoEasy library. Let's improve the timeseries classes to receive data from any timeframes to display it on the current chart period.
Developing a cross-platform grid EA: testing a multi-currency EA

Developing a cross-platform grid EA: testing a multi-currency EA

Markets dropped down by more that 30% within one month. It seems to be the best time for testing grid- and martingale-based Expert Advisors. This article is an unplanned continuation of the series "Creating a Cross-Platform Grid EA". The current market provides an opportunity to arrange a stress rest for the grid EA. So, let's use this opportunity and test our Expert Advisor.
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Continuous Walk-Forward Optimization (Part 6): Auto optimizer's logical part and structure

We have previously considered the creation of automatic walk-forward optimization. This time, we will proceed to the internal structure of the auto optimizer tool. The article will be useful for all those who wish to further work with the created project and to modify it, as well as for those who wish to understand the program logic. The current article contains UML diagrams which present the internal structure of the project and the relationships between objects. It also describes the process of optimization start, but it does not contain the description of the optimizer implementation process.
MQL as a Markup Tool for the Graphical Interface of MQL Programs. Part 2

MQL as a Markup Tool for the Graphical Interface of MQL Programs. Part 2

This paper continues checking the new conception to describe the window interface of MQL programs, using the structures of MQL. Automatically creating GUI based on the MQL markup provides additional functionality for caching and dynamically generating the elements and controlling the styles and new schemes for processing the events. Attached is an enhanced version of the standard library of controls.
Timeseries in DoEasy library (part 39): Library-based indicators - preparing data and timeseries events

Timeseries in DoEasy library (part 39): Library-based indicators - preparing data and timeseries events

The article deals with applying DoEasy library for creating multi-symbol multi-period indicators. We are going to prepare the library classes to work within indicators and test creating timeseries to be used as data sources in indicators. We will also implement creating and sending timeseries events.
Multicurrency monitoring of trading signals (Part 4): Enhancing functionality and improving the signal search system

Multicurrency monitoring of trading signals (Part 4): Enhancing functionality and improving the signal search system

In this part, we expand the trading signal searching and editing system, as well as introduce the possibility to use custom indicators and add program localization. We have previously created a basic system for searching signals, but it was based on a small set of indicators and a simple set of search rules.
MQL as a Markup Tool for the Graphical Interface of MQL Programs. Part 1

MQL as a Markup Tool for the Graphical Interface of MQL Programs. Part 1

This paper proposes a new conception to describe the window interface of MQL programs, using the structures of MQL. Special classes transform the viewable MQL markup into the GUI elements and allow manage them, set up their properties, and process the events in a unified manner. It also provides some examples of using the markup for the dialogs and elements of a standard library.
Timeseries in DoEasy library (part 38): Timeseries collection - real-time updates and accessing data from the program

Timeseries in DoEasy library (part 38): Timeseries collection - real-time updates and accessing data from the program

The article considers real-time update of timeseries data and sending messages about the "New bar" event to the control program chart from all timeseries of all symbols for the ability to handle these events in custom programs. The "New tick" class is used to determine the need to update timeseries for the non-current chart symbol and periods.
Multicurrency monitoring of trading signals (Part 3): Introducing search algorithms

Multicurrency monitoring of trading signals (Part 3): Introducing search algorithms

In the previous article, we developed the visual part of the application, as well as the basic interaction of GUI elements. This time we are going to add internal logic and the algorithm of trading signal data preparation, as well us the ability to set up signals, to search them and to visualize them in the monitor.
Applying OLAP in trading (part 4): Quantitative and visual analysis of tester reports

Applying OLAP in trading (part 4): Quantitative and visual analysis of tester reports

The article offers basic tools for the OLAP analysis of tester reports relating to single passes and optimization results. The tool can work with standard format files (tst and opt), and it also provides a graphical interface. MQL source codes are attached below.
Timeseries in DoEasy library (part 37): Timeseries collection - database of timeseries by symbols and periods

Timeseries in DoEasy library (part 37): Timeseries collection - database of timeseries by symbols and periods

The article deals with the development of the timeseries collection of specified timeframes for all symbols used in the program. We are going to develop the timeseries collection, the methods of setting collection's timeseries parameters and the initial filling of developed timeseries with historical data.
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Continuous Walk-Forward Optimization (Part 5): Auto Optimizer project overview and creation of a GUI

This article provides further description of the walk-forward optimization in the MetaTrader 5 terminal. In previous articles, we considered methods for generating and filtering the optimization report and started analyzing the internal structure of the application responsible for the optimization process. The Auto Optimizer is implemented as a C# application and it has its own graphical interface. The fifth article is devoted to the creation of this graphical interface.
Forecasting Time Series (Part 2): Least-Square Support-Vector Machine (LS-SVM)

Forecasting Time Series (Part 2): Least-Square Support-Vector Machine (LS-SVM)

This article deals with the theory and practical application of the algorithm for forecasting time series, based on support-vector method. It also proposes its implementation in MQL and provides test indicators and Expert Advisors. This technology has not been implemented in MQL yet. But first, we have to get to know math for it.
Projects assist in creating profitable trading robots! Or at least, so it seems

Projects assist in creating profitable trading robots! Or at least, so it seems

A big program starts with a small file, which then grows in size as you keep adding more functions and objects. Most robot developers utilize include files to handle this problem. However, there is a better solution: start developing any trading application in a project. There are so many reasons to do so.
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Continuous Walk-Forward Optimization (Part 4): Optimization Manager (Auto Optimizer)

The main purpose of the article is to describe the mechanism of working with our application and its capabilities. Thus the article can be treated as an instruction on how to use the application. It covers all possible pitfalls and specifics of the application usage.
Timeseries in DoEasy library (part 36): Object of timeseries for all used symbol periods

Timeseries in DoEasy library (part 36): Object of timeseries for all used symbol periods

In this article, we will consider combining the lists of bar objects for each used symbol period into a single symbol timeseries object. Thus, each symbol will have an object storing the lists of all used symbol timeseries periods.
Forecasting Time Series (Part 1): Empirical Mode Decomposition (EMD) Method

Forecasting Time Series (Part 1): Empirical Mode Decomposition (EMD) Method

This article deals with the theory and practical use of the algorithm for forecasting time series, based on the empirical decomposition mode. It proposes the MQL implementation of this method and presents test indicators and Expert Advisors.
Timeseries in DoEasy library (part 35): Bar object and symbol timeseries list

Timeseries in DoEasy library (part 35): Bar object and symbol timeseries list

This article starts a new series about the creation of the DoEasy library for easy and fast program development. In the current article, we will implement the library functionality for accessing and working with symbol timeseries data. We are going to create the Bar object storing the main and extended timeseries bar data, and place bar objects to the timeseries list for convenient search and sorting of the objects.
Multicurrency monitoring of trading signals (Part 2): Implementation of the visual part of the application

Multicurrency monitoring of trading signals (Part 2): Implementation of the visual part of the application

In the previous article, we created the application framework, which we will use as the basis for all further work. In this part, we will proceed with the development: we will create the visual part of the application and will configure basic interaction of interface elements.
Applying network functions, or MySQL without DLL: Part II - Program for monitoring changes in signal properties

Applying network functions, or MySQL without DLL: Part II - Program for monitoring changes in signal properties

In the previous part, we considered the implementation of the MySQL connector. In this article, we will consider its application by implementing the service for collecting signal properties and the program for viewing their changes over time. The implemented example has practical sense if users need to observe changes in properties that are not displayed on the signal's web page.
Library for easy and quick development of MetaTrader programs (part XXXIV): Pending trading requests - removing and modifying orders and positions under certain conditions

Library for easy and quick development of MetaTrader programs (part XXXIV): Pending trading requests - removing and modifying orders and positions under certain conditions

In this article, we will complete the description of the pending request trading concept and create the functionality for removing pending orders, as well as modifying orders and positions under certain conditions. Thus, we are going to have the entire functionality enabling us to develop simple custom strategies, or rather EA behavior logic activated upon user-defined conditions.
Applying network functions, or MySQL without DLL: Part I - Connector

Applying network functions, or MySQL without DLL: Part I - Connector

MetaTrader 5 has received network functions recently. This opened up great opportunities for programmers developing products for the Market. Now they can implement things that required dynamic libraries before. In this article, we will consider them using the implementation of the MySQL as an example.
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How to create 3D graphics using DirectX in MetaTrader 5

3D graphics provide excellent means for analyzing huge amounts of data as they enable the visualization of hidden patterns. These tasks can be solved directly in MQL5, while DireсtX functions allow creating three-dimensional object. Thus, it is even possible to create programs of any complexity, even 3D games for MetaTrader 5. Start learning 3D graphics by drawing simple three-dimensional shapes.
Library for easy and quick development of MetaTrader programs (part XXXIII): Pending trading requests - closing positions under certain conditions

Library for easy and quick development of MetaTrader programs (part XXXIII): Pending trading requests - closing positions under certain conditions

We continue the development of the library functionality featuring trading using pending requests. We have already implemented sending conditional trading requests for opening positions and placing pending orders. In the current article, we will implement conditional position closure – full, partial and closing by an opposite position.
Applying OLAP in trading (part 3): Analyzing quotes for the development of trading strategies

Applying OLAP in trading (part 3): Analyzing quotes for the development of trading strategies

In this article we will continue dealing with the OLAP technology applied to trading. We will expand the functionality presented in the first two articles. This time we will consider the operational analysis of quotes. We will put forward and test the hypotheses on trading strategies based on aggregated historical data. The article presents Expert Advisors for studying bar patterns and adaptive trading.
Library for easy and quick development of MetaTrader programs (part XXXII): Pending trading requests - placing orders under certain conditions

Library for easy and quick development of MetaTrader programs (part XXXII): Pending trading requests - placing orders under certain conditions

We continue the development of the functionality allowing users to trade using pending requests. In this article, we are going to implement the ability to place pending orders under certain conditions.
Library for easy and quick development of MetaTrader programs (part XXXI): Pending trading requests - opening positions under certain conditions

Library for easy and quick development of MetaTrader programs (part XXXI): Pending trading requests - opening positions under certain conditions

Starting with this article, we are going to develop a functionality allowing users to trade using pending requests under certain conditions, for example, when reaching a certain time limit, exceeding a specified profit or closing a position by stop loss.
Multicurrency monitoring of trading signals (Part 1): Developing the application structure

Multicurrency monitoring of trading signals (Part 1): Developing the application structure

In this article, we will discuss the idea of creating a multicurrency monitor of trading signals and will develop a future application structure along with its prototype, as well as create its framework for further operation. The article presents a step-by-step creation of a flexible multicurrency application which will enable the generation of trading signals and which will assist traders in finding the desired signals.
Econometric approach to finding market patterns: Autocorrelation, Heat Maps and Scatter Plots

Econometric approach to finding market patterns: Autocorrelation, Heat Maps and Scatter Plots

The article presents an extended study of seasonal characteristics: autocorrelation heat maps and scatter plots. The purpose of the article is to show that "market memory" is of seasonal nature, which is expressed through maximized correlation of increments of arbitrary order.
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Continuous Walk-Forward Optimization (Part 3): Adapting a Robot to Auto Optimizer

Continuous Walk-Forward Optimization (Part 3): Adapting a Robot to Auto Optimizer

The third part serves as a bridge between the previous two parts: it describes the mechanism of interaction with the DLL considered in the first article and the objects for report downloading, which were described in the second article. We will analyze the process of wrapper creation for a class which is imported from DLL and which forms an XML file with the trading history. We will also consider a method for interacting with this wrapper.
Library for easy and quick development of MetaTrader programs (part XXX): Pending trading requests - managing request objects

Library for easy and quick development of MetaTrader programs (part XXX): Pending trading requests - managing request objects

In the previous article, we have created the classes of pending request objects corresponding to the general concept of library objects. This time, we are going to deal with the class allowing the management of pending request objects.
Library for easy and quick development of MetaTrader programs (part XXIX): Pending trading requests - request object classes

Library for easy and quick development of MetaTrader programs (part XXIX): Pending trading requests - request object classes

In the previous articles, we checked the concept of pending trading requests. A pending request is, in fact, a common trading order executed by a certain condition. In this article, we are going to create full-fledged classes of pending request objects — a base request object and its descendants.
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Neural Networks Made Easy

Neural Networks Made Easy

Artificial intelligence is often associated with something fantastically complex and incomprehensible. At the same time, artificial intelligence is increasingly mentioned in everyday life. News about achievements related to the use of neural networks often appear in different media. The purpose of this article is to show that anyone can easily create a neural network and use the AI achievements in trading.
Library for easy and quick development of MetaTrader programs (part XXVIII): Closure, removal and modification of pending trading requests

Library for easy and quick development of MetaTrader programs (part XXVIII): Closure, removal and modification of pending trading requests

This is the third article about the concept of pending requests. We are going to complete the tests of pending trading requests by creating the methods for closing positions, removing pending orders and modifying position and pending order parameters.
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SQLite: Native handling of SQL databases in MQL5

SQLite: Native handling of SQL databases in MQL5

The development of trading strategies is associated with handling large amounts of data. Now, you are able to work with databases using SQL queries based on SQLite directly in MQL5. An important feature of this engine is that the entire database is placed in a single file located on a user's PC.
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Continuous Walk-Forward Optimization (Part 2): Mechanism for creating an optimization report for any robot

Continuous Walk-Forward Optimization (Part 2): Mechanism for creating an optimization report for any robot

The first article within the Walk-Through Optimization series described the creation of a DLL to be used in our auto optimizer. This continuation is entirely devoted to the MQL5 language.
Library for easy and quick development of MetaTrader programs (part XXVII): Working with trading requests - placing pending orders

Library for easy and quick development of MetaTrader programs (part XXVII): Working with trading requests - placing pending orders

In this article, we will continue the development of trading requests, implement placing pending orders and eliminate detected shortcomings of the trading class operation.
Library for easy and quick development of MetaTrader programs (part XXVI): Working with pending trading requests - first implementation (opening positions)

Library for easy and quick development of MetaTrader programs (part XXVI): Working with pending trading requests - first implementation (opening positions)

In this article, we are going to store some data in the value of the orders and positions magic number and start the implementation of pending requests. To check the concept, let's create the first test pending request for opening market positions when receiving a server error requiring waiting and sending a repeated request.
Exploring Seasonal Patterns of Financial Time Series with Boxplot

Exploring Seasonal Patterns of Financial Time Series with Boxplot

In this article we will view seasonal characteristics of financial time series using Boxplot diagrams. Each separate boxplot (or box-and-whiskey diagram) provides a good visualization of how values are distributed along the dataset. Boxplots should not be confused with the candlestick charts, although they can be visually similar.
Library for easy and quick development of MetaTrader programs (part XXV): Handling errors returned by the trade server

Library for easy and quick development of MetaTrader programs (part XXV): Handling errors returned by the trade server

After we send a trading order to the server, we need to check the error codes or the absence of errors. In this article, we will consider handling errors returned by the trade server and prepare for creating pending trading requests.