Designing MQL5 Classes Around Events and Modular Components
Summary
This tutorial explains object-oriented programming concepts in MQL5 through a visual interface project. It introduces event-driven program flow and the roles of encapsulation, inheritance, and polymorphism, then applies them to a hierarchy of cells, rows, and a window. The design process begins with a sketch of the interface and uses that structure to identify components, their properties, and how they fit together. A shared structure carries cell properties between classes, while class methods draw elements and process chart events.
The example connects the main window module to the Expert Advisor lifecycle and chart-event handlers. It recommends designing classes incrementally, dividing work into modules and smaller components, and keeping base classes lean. The article is a programming and interface-design guide rather than a trading strategy: it does not show a market model, trading results, or evidence that object-oriented design improves profitability. It also acknowledges that OOP is optional and does not guarantee successful trading robots; its value here is support for organizing extensible software.
Key ideas
- MQL5 programs respond to events through handlers such as initialization, ticks, timers, and chart events.
- Encapsulation, inheritance, and polymorphism provide ways to organize class behavior and reuse components.
- A visual design can be decomposed into cells, rows, and a containing window class.
- Shared structures can carry properties between components as the design evolves.
- Keep base classes focused and add complexity only as the project requires it.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.