如何捕获广播消息？

[najzni]

在一个进程的线程中::PostMessage（HWND_BROADCAST，WM_TEST,0,0);
那么在另一个进程中如何捕获该消息？

[stevecrisewu]

GetMessage
The GetMessage function retrieves a message from the calling thread's message queue. The function dispatches incoming sent messages until a posted message is available for retrieval.

Unlike GetMessage, the PeekMessage function does not wait for a message to be posted before returning.

BOOL GetMessage(
LPMSG lpMsg, // message information
HWND hWnd, // handle to window
UINT wMsgFilterMin, // first message
UINT wMsgFilterMax // last message
);
Parameters
lpMsg
[out] Pointer to an MSG structure that receives message information from the thread's message queue.
hWnd
[in] Handle to the window whose messages are to be retrieved. The window must belong to the calling thread. The following value has a special meaning. Value Meaning
NULL GetMessage retrieves messages for any window that belongs to the calling thread and thread messages posted to the calling thread using the PostThreadMessage function.


wMsgFilterMin
[in] Specifies the integer value of the lowest message value to be retrieved.
wMsgFilterMax
[in] Specifies the integer value of the highest message value to be retrieved.
Return Values
If the function retrieves a message other than WM_QUIT, the return value is nonzero.

If the function retrieves the WM_QUIT message, the return value is zero.

If there is an error, the return value is -1. For example, the function fails if hWnd is an invalid window handle or lpMsg is an invalid pointer. To get extended error information, call GetLastError.

Warning Because the return value can be nonzero, zero, or -1, avoid code like this:

while (GetMessage( lpMsg, hWnd, 0, 0)) ...
The possibility of a -1 return value means that such code can lead to fatal application errors.

[najzni]

试过，这样好像不行。

[wqs_qiu_shi]

两个程序中要注册同样的消息名称

UINT nMsgID = RegisterWindowMessage("wqs");
::PostMessage(HWND_BROADCAST,nMsgID,wParam,lParam);

------------------------
recv:
m_nMsgID = RegisterWindowMessage("wqs");
PreTranslateMessage(MSG* pMsg)中:
if( pMsg->message == m_nMsgID )
AfxMessageBox("ok!");

[Anikan]

你必须在TOP_LEVEL的窗口中(不是子窗口）捕获这个消息。具体的你可以查看MSDN对PostMessage 中当HWND == HWND_BROADCAST的解释。