private bool isMouseDown = false;
        private Point mouseOffset; //记录鼠标指针的坐标
        int button1_point = 10000000;

        private void button1_MouseDown(object sender, MouseEventArgs e)
        {
            if (button1.Left != button1_point && button1_point != 10000000)
            {
                isMouseDown = false;
                button1_point = 10000000;
                return;
            }
            if (e.Button == MouseButtons.Left)
            {
                button1_point = button1.Left;
                mouseOffset.X = e.X;
                mouseOffset.Y = e.Y;
                isMouseDown = true;
            }
        }

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

用这种方法 移动控件 如果鼠标移动太快，会把 控件甩丢 有什么好的解决方案，控制 移动的控件必须跟紧鼠标 或者防止甩下移动的控件，就把对应移动的控件 返回到 原来的 Location里面