问题描述
在我的应用程序中，我需要处理鼠标悬停事件以更改按钮的背景.使用MFC类向导，我在该项目的事件列表中找不到鼠标悬停条目.我尝试使用PreTranslateMessage，但是它不起作用.我该如何处理该事件?
In my application I need to handle mouse hover event to change the background of a button. Using the MFC class wizard, I couldn't find a mouse hover entry in the list of events for that item. I tried using PreTranslateMessage, but it doesn't work. How can I handle that event?
推荐答案
默认情况下不会生成鼠标悬停事件.您必须通过调用 TrackMouseEvent 来请求它们正确填充的 TRACKMOUSEEVENT结构:
Mouse hover events aren't generated by default. You have to request them by calling TrackMouseEvent with a properly populated TRACKMOUSEEVENT structure:
TRACKMOUSEEVENT tme = { 0 };
tme.cbSize = sizeof( tme );
tme.dwFlags = TME_HOVER;
tme.hwndTrack = myButton;
tme.dwHoverTime = myHoverTime; // HOVER_DEFAULT, or the hover timeout in milliseconds.
::TrackMouseEvent( &tme );
然后，系统将生成 WM_MOUSEHOVER 消息如果鼠标悬停在 myButton 上 myHoverTime 毫秒.
The system will then generate WM_MOUSEHOVER messages if the mouse hovers over myButton for myHoverTime milliseconds.
由于WM_MOUSEHOVER消息已发布到请求鼠标悬停消息的窗口，因此您将必须派生自定义按钮控件，并在其消息映射中添加适当的条目.特别是，您将必须使用ON_WM_MOUSEHOVER()宏并实现 afx_msg void OnMouseHover (UINT，CPoint)(请参见 WM_消息处理程序:L-M 供参考).
Since the WM_MOUSEHOVER message is posted to the window that requested mouse hover messages, you will have to derive a custom button control, with appropriate entries in its message map. In particular, you will have to use the ON_WM_MOUSEHOVER() macro and implement afx_msg void OnMouseHover(UINT, CPoint) (see WM_ Message Handlers: L - M for reference).
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