protected virtual IntPtr OwnerWndProc(IntPtr hWnd, int msg, IntPtr wparam, IntPtr lparam)
{
if (msg == helpMsg)
{
try {
OnHelpRequest(EventArgs.Empty);
}
catch (Exception e) {
Application.OnThreadException(e);
}
return(IntPtr.Zero);
}
return(UnsafeNativeMethods.CallWindowProc(defOwnerWndProc, hWnd, msg, wparam, lparam));
}
/// <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 = UnsafeNativeMethods.DefWindowProc(m.HWnd, m.Msg, m.WParam, m.LParam);
return;
}
m.Result = UnsafeNativeMethods.CallWindowProc(_priorWindowProcHandle, m.HWnd, m.Msg, m.WParam, m.LParam);
}
else
{
m.Result = PreviousWindow.Callback(m.HWnd, (User32.WindowMessage)m.Msg, m.WParam, m.LParam);
}
}
