什么是无效，更新方法在 VC++ 中的作用 [英] what is invalidate,update methods do in VC++

问题描述

我对 c++ 中的窗口函数有一点怀疑."invalidate()" 函数到底是做什么的?它发送什么消息?我们什么时候需要调用它?"update()" 函数又是什么?"invalidaterect()" 是否与 "invalidate()" 功能类似?

i have small doubt regarding the window functions in c++. what exactly "invalidate()" function do? what message does it sends?when we need to call this? also what is "update()" function? is "invalidaterect()" works similar to "invalidate()" function?.

谢谢

推荐答案

CWnd::Invalidate() 使窗口的整个客户区无效，这表明该区域已过时，应重新绘制.您通常会在需要重绘的控件上调用它.CWnd::InvalidateRect() 仅使窗口的一部分无效.

CWnd::Invalidate() invalidates the entire client area of a window, which indicates that the area is out of date, and should be repainted. You would typically call this on a control that needs to be redrawn. CWnd::InvalidateRect() invalidates only part of the window.

使用 Invalidate 函数，WM_PAINT 消息将发布 [严格来说不正确；查看消息队列的评论]，并在将来的某个时间处理.CWnd::UpdateWindow() 发送(相对于帖子)WM_PAINT 消息，导致无效区域立即重绘.

With the Invalidate functions, the WM_PAINT message will posted [not strictly true; see the comments] to the message queue and handled at some point in the future. CWnd::UpdateWindow() sends (as opposed to posts) a WM_PAINT message, causing the invalidated regions to be redrawn immediately.

真的，这些都在文档中.

Really, this is all in the docs.

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