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. Only use RegisterWindowMessage when more than one application must process the same message. For sending private messages within a window class, an application can use any integer in the range WM_USER through 0x7FFF. (Messages in this range are private to a window class, not to an application. For example, predefined control classes such as BUTTON, EDIT, LISTBOX, and COMBOBOX may use values in this range.)
当我用RegisterWindowMessage()定义了一个Windows消息, 当这个应用送出这个消息,当前应用的窗口将收到消息.而另外一个应用如果定义了同样的消息,它的窗口也可以收到这个消息,尽管这个消息不是它本身的应用发出的.
明天给分.