Перетаскивание форм в C#

this.Capture = false;
var msg = Message.Create(this.Handle, 0xa1, new IntPtr(2), IntPtr.Zero);
this.WndProc(ref msg);

class MyForm : Form
{
   ...
 
   Point last;
   
   void Form_MouseDown (object sender, MouseEventArgs e)
   {
      if (e.Button == MouseButtons.Left) {
         last = MousePosition;
      }
   }
 
   void Form_MouseMove (object sender, MouseEventArgs e)
   {
      if (e.Button == MouseButtons.Left) {
         Point cur = MousePosition;
         int dx = cur.X - last.X;
         int dy = cur.Y - last.Y;
         Point loc = new Point(Location.X + dx, Location.Y + dy);
         Location = loc;
         last = cur;
      }
   }
}

    public partial class frm_Menu : Form
    {
        const int WM_NCLBUTTONDOWN = 0xA1;
        const int HTCAPTION = 0x2;
        [DllImportAttribute("user32.dll")]
        static extern bool ReleaseCapture();
        [DllImportAttribute("user32.dll")]
        static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
 
        private void frm_Menu_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                ReleaseCapture();
                SendMessage(Handle, WM_NCLBUTTONDOWN, HTCAPTION, 0);
            }
        }
    }