WinForm中禁止窗体移动

窗体 form = new 窗体();
form.StartPosition = FormStartPosition.Manual;
form.Location = new Point(300, 0);
form.Show();

public const int WM_SYSCOMMAND = 0x112;
public const int SC_MOVE = 0xF012;

protected override void WndProc(ref   Message m)
{
if (m.Msg == WM_SYSCOMMAND)
{
if ((int)m.WParam == SC_MOVE)
return;
}
base.WndProc(ref   m);
}