WM_SYSCOMMAND消息是MFC预定义好的一组命令消息,框架有默认的处理方式,比如点击窗口右上方的关闭按钮,发送SC_CLOSE消息,用以关闭窗口。
系统命令消息包括以下几种:
SC_CLOSE
Closes the window.
SC_CONTEXTHELP
Changes the cursor to a question mark with a pointer. If the user then clicks a control in the dialog box, the control receives a
WM_HELP message.
SC_DEFAULT
Selects the default item; the user double-clicked the window menu.
SC_HOTKEY
Activates the window associated with the application-specified hot key. The
lParam parameter identifies the window to activate.
SC_HSCROLL
Scrolls horizontally.
SC_KEYMENU
Retrieve