nType表示窗口尺寸变化的类型,有最大化SIZE_MAXIMIZED 。最小化等等。
另外两个参数表示窗口新的客户区大小。
这个函数可以查阅MSDN
afx_msg void OnSize( UINT nType, int cx, int cy );
Parameters
nType
Specifies the type of resizing requested. This parameter can be one of the following values:
SIZE_MAXIMIZED Window has been maximized.
SIZE_MINIMIZED Window has been minimized.
SIZE_RESTORED Window has been resized, but neither SIZE_MINIMIZED nor SIZE_MAXIMIZED applies.
SIZE_MAXHIDE Message is sent to all pop-up windows when some other window is maximized.
SIZE_MAXSHOW Message is sent to all pop-up windows when some other window has been restored to its former size.
cx
Specifies the new width of the client area.
cy
Specifies the new height of the client area.