[Tutorial] Move form with no border

Just add the below snippet to your code (C#):

private const int WM_NCHITTEST = 0x84; // Mouse capture.
private const int HTCLIENT = 0x1;      // Client area.
private const int HTCAPTION = 0x2;     // Title bar.

// This function intercepts all the commands sent to the application.
// It checks if user click (WM_NCHITTEST) on the form area (HTCLIENT)
// It fakes the result as the title bar (HTCAPTION)
// This makes the form thinks user clicked on the title bar.
// So we can click and move form by (fake) title bar.
protected override void WndProc(ref Message message)
{
    base.WndProc(ref message);

    if (message.Msg == WM_NCHITTEST && (int)message.Result == HTCLIENT)
    {
        message.Result = (IntPtr)HTCAPTION;
    }
}