控件拖拽基本方法

//在窗体放置一个按钮  button1

         private bool isMouseDown = false;  //记录按钮是否被按下
        private Point mouseOffset;              //记录鼠标指针的坐标

        public Form1()
        {
            InitializeComponent();

            this.button1.MouseMove += new MouseEventHandler(button1_MouseMove);
            this.button1.MouseDown += new MouseEventHandler(button1_MouseDown);
            this.button1.MouseUp += new MouseEventHandler(button1_MouseUp);
        }

        void button1_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                isMouseDown = false;     //如果左边按钮弹起
            }
        }

        void button1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                mouseOffset.X = e.X;
                mouseOffset.Y = e.Y;
                isMouseDown = true;
            }
        
        }

        void button1_MouseMove(object sender, MouseEventArgs e)
        {
            if (isMouseDown)
            {
                int left = button1.Left + e.X - mouseOffset.X;
                int top = button1.Top + e.Y - mouseOffset.Y;
                button1.Location = new Point(left, top);
            }
        }