private const int WM_NCLBUTTONDOWN = 0x00A1; private  const int HTCAPTION = 2; [DllImport("user32.dll", CharSet = CharSet.Unicode)] public static extern IntPtr SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, IntPtr lParam); [DllImport("user32.dll", CharSet = CharSet.Unicode)] public static extern bool ReleaseCapture(); protected override void OnMouseDown( MouseEventArgs e ) {     base.OnMouseDown( e );     if (e.Button == MouseButtons.Left)  // 按下的是鼠标左键                  {         ReleaseCapture();   // 释放捕获                         SendMessage(this.Handle, WM_NCLBUTTONDOWN, (IntPtr)HTCAPTION, IntPtr.Zero);    // 拖动窗体                  } }