能获得当前窗体的句柄并且能获得此窗体内所有控件的句柄，也能获得鼠标所在处的窗体的句柄和其内的所有控件的句柄。-To get a handle to the current form and have access to all the controls inside the window handle, but also to get the mouse location in the form of the handle and all the controls inside the handle.