C # WinForm remove a border and implement the drag function

In WinForm, when we put the properties of the form

FormBorderStyle

When you indicate that the appearance and behavior of the form's border and title bar are set to none, we find that the ability to drag the form disappears, and we can use the MouseDown event to register the ability to drag the mobile form, using the Windows API to implement the code as follows

[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 Frmgampackagingscaledualsimple_mousedown (object sender, MouseEventArgs e)
{
if (E.button = = MouseButtons.Left)
{
ReleaseCapture ();
SendMessage (Handle, 0xa1, 0x02, 0);
}
}

C # WinForm remove a border and implement the drag function