using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    class DdBotton : Button
    {
        public DdBotton()
        {
            this.MouseDown += new MouseEventHandler(DdBotton_MouseDown);
            this.MouseUp += new MouseEventHandler(DdBotton_MouseUp);
            this.MouseMove += new MouseEventHandler(DdBotton_MouseMove);
        }
        Point MousePoint;
        void DdBotton_MouseMove(object sender, MouseEventArgs e)
        {
            if ((e.Button & MouseButtons.Left) == MouseButtons.Left)
            {
                if (this.MousePoint != Point.Empty)
                {
                    this.Left += e.X - this.MousePoint.X;
                    this.Top += e.Y - this.MousePoint.Y;
                }
            }
        }

        void DdBotton_MouseUp(object sender, MouseEventArgs e)
        {
            this.MousePoint = Point.Empty;
        }

        void DdBotton_MouseDown(object sender, MouseEventArgs e)
        {
            if((e.Button & MouseButtons.Left) == MouseButtons.Left)
            {
                if (this.MousePoint == Point.Empty)
                {
                    this.MousePoint = new Point(e.X, e.Y);
                }
            }
        }
    }
}