事实上是使用SetWindowPos()来改变z-order,所谓z-order是屏幕一般是以x轴y轴
来表示位置,而以z轴表示前後位置,这便是z-order
bWndInsertAfter的设定值
HWND_BOTTOM Places the window at the bottom of the Z order. If the hwnd
parameter identifies a topmost window, the window loses its
topmost status and is placed at the bottom of all other
windows.
HWND_NOTOPMOST Places the window above all non-topmost windows (that is,
behind all topmost windows). This flag has no effect if the
window is already a non-topmost window.[ 查看全文 ]