W indows is built on messages. When the users press one of the mouse buttons or a key, when they resize a window, or when they select a menu item, a message is generated and sent to the current appropriate class.

The messages are routed by a message map. The map is generated by the Application Wizard. It can be modified manually or with the Properties Window View (the Messages or Events button).

The message map is declared in the file class' header file as follows:

DECLARE_MESSAGE_MAP()

The message map is implemented in the class' implementation file as follows:

BEGIN_MESSAGE_MAP(this_class, base_class)
  // Message handlers.
END_MESSAGE_MAP()

Each message has it own handle, and is connected to a method of a specific form that catches the message. There are different handlers for different types of messages. There are around 200 messages in Windows. Here follows a table with the most common ones. Note that we do not have to catch every message. We just catch those we are interested...