setparent . If this parameter is NULL, the desktop window becomes the new parent window.
SetParent does not modify the WS_CHILD or WS_POPUP window styles of the window whose parent is being changed. Therefore, if hWndNewParent is NULL, you should also clear the WS_CHILD bit and set the WS_POPUP style after calling SetParent
. If this parameter is NULL, the desktop window becomes the new parent window.
然后把窗口属性改成popup!