拖动无标题窗口

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

...

..

.

[STAThread]
        static void Main() 
        {
            Application.Run(new Form1());
        }

        [DllImport("user32.dll")]
        public static extern bool ReleaseCapture();
        [DllImport("user32.dll")]
        public static extern bool SendMessage(IntPtr hwnd,int wMsg,int wParam,int lParam);                                                                                                                                                         
        public const int WM_SYSCOMMAND=0x0112;
        public const int SC_MOVE=0xF010;
        public const int HTCAPTION=0x0002;

        private void button2_Click(object sender, System.EventArgs e)
        {//关闭应用程序
            this.Close();        
        }

        private void button1_Click(object sender, System.EventArgs e)
        {//显示标题栏
            if(this.button1.Text=="显示标题栏")
            {
                this.FormBorderStyle=FormBorderStyle.Fixed3D;
                this.button1.Text="关闭标题栏";
            }
            else
            {
                this.FormBorderStyle=FormBorderStyle.None;
                this.button1.Text="显示标题栏";            
            }
        }
        private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
        {//拖动窗体
            ReleaseCapture();
            SendMessage(this.Handle,WM_SYSCOMMAND,SC_MOVE+HTCAPTION, 0); 
        }
    }