C# winform无标题窗体随意移动

        /// <summary>
        /// 下面这段代码是用来实现窗体随意移动
        /// </summary>
        /// <param name="m"></param>
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == 0x0201)
            {
                m.Msg = 0x00A1;//更改消息为非客户区按下鼠标
                m.LParam = IntPtr.Zero;
                m.WParam = new IntPtr(2);//鼠标放在标题栏内
            }
            base.WndProc(ref m);
        }