诊断神秘WM_PAINT消息 [英] Diagnose mystery WM_PAINT message

问题描述

我有一个神秘的WM_PAINT消息被发送到窗口，没有理由我可以can。。我从一些代码发送一个WM_PAINT消息使用 -

  InvalidateRgn（graphwin_hwnd，NULL，1）; 
 SendMessage（graphwin_hwnd，WM_PAINT，0,0）; 
  

但是在执行在屏幕上绘制一些图形的后续代码后，调试器指示第二个WM_PAINT消息从某处到达。我的问题是，如何诊断是什么导致发送第二个WM_PAINT消息。

编辑：i486正确地指出不需要显式地做SendMessage（）...但令我惊讶的是，即使我评论它，我仍然得到1多余的神秘WM_PAINT消息发送到我的图形窗口的处理程序，所以它不是很完全解决问题

编辑：糟糕，我错了，在注释掉SendMessage后，它似乎还有一个无关的错误，我只收到一个WM_PAINT消息...所以问题解决。

解决方案

您不需要发送WM_PAINT - Invalidate后自动发送。调用 UpdateWindow 强制它。可能第二个WM_PAINT是因为 InvalidateRgn 。要测试这个，请注释 SendMessage 并检查WM_PAINT。

I have a mystery WM_PAINT message being sent to a window for no reason that I can fathom. I am sending one WM_PAINT message from some code of mine using-

InvalidateRgn(graphwin_hwnd,NULL,1);
SendMessage(graphwin_hwnd,WM_PAINT,0,0);

but after executing the subsequent code that draws some graphics on the screen, the debugger indicates that a second WM_PAINT message arrives from somewhere. My question is, how can I diagnose what is causing this second WM_PAINT message to be sent.

Edit: i486 has correctly pointed out that I didn't need to explicitly do the SendMessage()... but to my surprise, even when I commented it out, I still get 1 excess mystery WM_PAINT message being sent to the handler for my graphics window, so it's not quite problem solved yet.

Edit: Oops, I was mistaken, after commenting out the SendMessage it seems I still had an unrelated bug screwing things up - but I did only get one WM_PAINT message... so problem solved.

解决方案

You don't need to send WM_PAINT - it is sent automatically after Invalidate. Call UpdateWindow to force it. Probably the second WM_PAINT is because of InvalidateRgn. To test this, comment your SendMessage and check for WM_PAINT.

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