ParentWindow is null

[olluz]

can you please check if the Parentwindow is null ?

If I add the UserControl as an ElementHost child (e.g. in my Outlook Addin) then it'll throw me an exception, because it is not loaded in a Window...

here:
if (_ParentWindow.FindChildByUid(Uid) == null)
and here:
_ParentWindow.Closed += _ParentWindowOnClosed;

Thanks

[djonasdev]

Thanks for the hint! This hook was inserted so that the following issue could be solved: #16

The UserControl is currently disposed of via the _ParentWindow.Closed EventHandler. That would no longer be the case and we would have a memory leak.

If you have a solution for me to solve your problem, I am happy to implement it!

[olluz]

I think you had this check before, but removed it for some reason.

May I suggest this simple change:
_ParentWindow = Window.GetWindow(this);
if (_ParentWindow != null)
{
_ParentWindow.Closed += _ParentWindowOnClosed;
}
ListView.ScrollToEnd();

[djonasdev]

..and when should Dispose (https://github.com/dojo90/NLogViewer/blob/master/src/NLogViewer/NLogViewer.xaml.cs#L490) be called?

[olluz]

The Unloaded event will still be called. And even though the _ParentWindow below is null it will not throw an exception (which is surprising to me).

private void _OnUnloaded(object sender, RoutedEventArgs e) { // look in logical and visual tree if the control has been removed if (_ParentWindow.FindChildByUid<NLogViewer>(Uid) == null) { _Dispose(); } }

So, Dispose is called in _OnUnloaded.

I don't see any down side in checking if the _ParentWindow is null, because if it is the WindowClosed event will never be called anyway...

[djonasdev]

The Unloaded event will still be called. And even though the _ParentWindow below is null it will not throw an exception (which is surprising to me).

Since the method is called recursive, no exception should be thrown here. See: https://github.com/dojo90/NLogViewer/blob/master/src/NLogViewer/Extensions/DependencyObjectExtensions.cs#L20

I don't see any down side in checking if the _ParentWindow is null, because if it is the WindowClosed event will never be called anyway...

This logic is needed if you use the NLogViewer on a TabControl inside of a new window/popup. If you change the TabItem, the UnLoaded handler is called and we need to check if the popup window is closed or just another TabItem is selected.

Could you please try the following commit whether it solves your problem? 92fb12b

[djonasdev]

Ah now I think I get it! 🤦‍♂️😂
Since null is returned if _ParentWindow == null I don't need the if else query!

[olluz]

yes, that works. Thanks a lot!