/// <summary>
/// Invokes the default window procedure associated with this Window. It is
/// an error to call this method when the Handle property is zero.
/// </summary>
public void DefWndProc(ref Message m)
{
if (PreviousWindow == null)
{
if (_priorWindowProcHandle == IntPtr.Zero)
{
Debug.Fail($"Can't find a default window procedure for message {m} on class {GetType().Name}");
// At this point, there isn't much we can do. There's a small chance the following
// line will allow the rest of the program to run, but don't get your hopes up.
m.Result = User32.DefWindowProcW(m.HWnd, m.WindowMessage(), m.WParam, m.LParam);
return;
}
m.Result = User32.CallWindowProcW(_priorWindowProcHandle, m.HWnd, m.WindowMessage(), m.WParam, m.LParam);
}
else
{
m.Result = PreviousWindow.Callback(m.HWnd, m.WindowMessage(), m.WParam, m.LParam);
}
}
