onsyscommand

OnSysCommand（）这个函数主要是截获控制命令的，msdn上的解释如下：

The framework calls this member function when the user selects a command from the Control menu, or when the user selects the Maximize or the Minimize button.

尤其是最大化和最小化窗口的时候，比如现在软件的流行的点关闭按钮，不是对出而是隐藏的情况，就可以在这里来实现，

void CMainFrame::OnSysCommand(UINT nID, LPARAM lParam)

{

if (nID == SC_CLOSE)

ShowWindow(SW_HIDE);

.....

}

就是这样来实现的，

注意和PreTranslateMessage的区别

PreTranslateMessage是用来截获消息的，msdn的解释如下

Used by class cwinapp to translate window messages before they are dispatched to the TranslateMessage and DispatchMessage Windows functions.

virtual BOOL PreTranslateMessage(

MSG* pMsg

);

nID

SC_CLOSEClose the CWnd object. //关闭

SC_MAXIMIZE (or SC_ZOOM)Maximize the CWnd object.//最大化

SC_MINIMIZE (or SC_ICON)Minimize the CWnd object.//最小化

SC_RESTORERestore window to normal position and size.//还原

SC_SIZESize the CWnd object. //大小

SC_MOVEMove the CWnd object.//移动