bug： OnIdle called only while mouse's moving

bug： OnIdle called only while mouse's moving

在mfc的group上有这样一个问题：（ http://msdn.microsoft.com/newsgroups/default.aspx?dg=microsoft.public.vc.mfc&mid=1aa1eddf-7bcf-407b-84fe-234fe0975331&sloc=en-us）

I need to update one  class  data and the view during the idle, I used  this   
method  in  the Cdoc:
void  CMyAppDoc::OnIdle(){

    theClass -> Update();
    POSITION pos  =  GetFirstViewPosition();
    CView *  pView  =  GetNextView(pos);
    pView -> Invalidate( true );
    pView -> UpdateWindow();    
}

It works only when I move the mouse, what ' s wrong? Z_Z

这个问题的确比较搞，要好好看mfc源码的，下面是我的回答
Nothing is wrong, I can explain it  is by design.
Please take a look at the source code of int CWinThread::Run(), in that function, IsIdleMessage() is called, and in IsIdleMessage() WM_PAINT is ignored, which means WM_PAINT will not cause OnIdle to be called, for windows think it's just a WM_PAINT message and will not change the UI.
Your UpdateWindow() only post a WM_PAINT message, the message queue is not empty but it's ignored by IsIdleMessage(), that's why.
But when you move your mouse, the message queue is filled with some WM_MOUSEMOVE and it's not ignored for the position changes. So your OnIdle() is called again.
-
My suggestion is to move your Invalidate & UpdateWindow code to somewhere else.
OnIdle（）的确是个有点复杂的问题，我可能还会写几篇文章 ：）
这里（ http://groups.google.com/group/microsoft.public.vc.mfc/browse_thread/thread/14f20aa5ffd6994d/66b6e5949a31bfa2?lnk=st&q=AfxUnlockTempMaps&rnum=40&hl=zh-CN#66b6e5949a31bfa2）有篇文章讲的很到位