应该说这不叫消息映射,其实就是消息的传递吧。
如果要传递自定义消息,首先应在DLL中调用RegisterWindowMessage函数,注册消息,
The RegisterWindowMessage function is typically used to register messages for communicating between two cooperating applications.
If two different applications register the same message string, the applications return the same message value. The message remains registered until the session ends.