C# 无窗体的窗口移动

using System.Runtime.InteropServices;

       public frmMain()
        {
            InitializeComponent();
            this.MouseDown += frmMain_MouseDown;
          //this.ListBox.MouseDown += frmMain_MouseDown;
        }

        //常量
        public const int WM_SYSCOMMAND = 0x0112;

        //窗体移动
        public const int SC_MOVE = 0xF010;
        public const int HTCAPTION = 0x0002;

        //改变窗体大小
        public const int WMSZ_LEFT = 0xF001;
        public const int WMSZ_RIGHT = 0xF002;
        public const int WMSZ_TOP = 0xF003;
        public const int WMSZ_TOPLEFT = 0xF004;
        public const int WMSZ_TOPRIGHT = 0xF005;
        public const int WMSZ_BOTTOM = 0xF006;
        public const int WMSZ_BOTTOMLEFT = 0xF007;
        public const int WMSZ_BOTTOMRIGHT = 0xF008;

        [DllImport("user32.dll")]
        public static extern bool ReleaseCapture();

        [DllImport("user32.dll")]
        public static extern bool SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);

        private void frmMain_MouseDown(object sender, MouseEventArgs e)
        {
            ReleaseCapture();
            SendMessage(this.Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0);
        }