c++ - GetMessage/PeekMessage - 删除消息队列中的所有消息

Question

我有以下代码

SendApp，点击按钮[X]时，执行以下代码

HWND pHWndReceiveApp = FindWindowA(NULL, "ReceiveApp");
    if (NULL == pHWndReceiveApp)
    {
        MessageBox(0, MSG_FAIL, CAPTION, 0);
        return;
    }
    for (int i = 0; i < 7; i++)
    {
        PostMessageA(pHWndReceiveApp, 9, 9, 0);
    }
    MessageBox(0, MSG_OK, CAPTION, 0);

ReceiveApp，这只是一个接收SendApp消息的应用

int i = 0;
msg.message = 69;
while (WM_QUIT != msg.message)
{
    if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE) > 0)
    {
        if (msg.message == 9)
        {
            //I want to remove all messages in the message queue before increase i
            ++i;
            Sleep(1000);
        }

        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

如您所见，我想在 ReceiveApp 中增加变量 i 之前删除消息队列中的所有消息。我读了this article看看那个

PM_REMOVE - Messages are removed from the queue after processing by PeekMessage.

我认为所有消息都应该被删除，但它们没有，在我按下 SendApp 中的按钮 [X] 后，ReceiveApp 中的变量 i 仍然增加了 7。

那么如何删除消息队列中的所有消息呢？

Answer 1

我明白了。我们可以在 while 循环中使用 PeekMessage 来清除队列中的消息，如下所示

#define ID 9
//...
int i = 0;
msg.message = 69;

while (GetMessage(&msg, 0, 0, 0))
{
    if (msg.message == ID)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
        while (PeekMessage(&msg, NULL, ID, ID, PM_REMOVE) > 0) //Clear message queue!
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        //I want to remove all message in the message queue before increase i
        ++i;
        Sleep(1000);
    }
}