鼠标轮滚动消息，WM_MOUSEWHEEL消息，lParam将获得鼠标的屏幕位置（坐标），wParam参数的低位表明鼠标键和Shift与Ctrl 键的状态。-Mouse wheel to scroll the message, WM_MOUSEWHEEL message, lParam will get the screen mouse position (coordinates), wParam parameter of the low that Shift and Ctrl key and mouse button state.