VC++限制鼠标的活动范围，将鼠标限制在一定的区域内移动，比如本程序中，就是把鼠标限制在仅和窗体大小一样的区域中，也就是鼠标不能移出窗体，在到达边缘的时候，鼠标不能再向外移动，当点击“释放鼠标”后，鼠标完全恢复正常状态。-VC++ to limit the scope of activities of the mouse, the mouse is limited to moving within a certain area, such as the program is limited to