public class MyForm : Form
{
// ..
private const int WM_NCHITTEST = 0x0084;
private const int HTCLIENT = 1;
private const int HTCAPTION = 2;
protected override void WndProc( ref Message m )
{
base.WndProc( ref m );
if ( m.Msg == WM_NCHITTEST )
{
if ( m.Result == ( IntPtr )HTCLIENT )
{
m.Result = ( IntPtr )HTCAPTION;
}
}
}
}