Binding issue about NonReloadingTabControl.cs

[NeverMorewd]

Is there an existing issue for this?

• I have searched both open/closed issues, no issue already exists.

CefSharp Version

108.4.13

Operating System

Windows 11

Architecture

x64

.Net Version

.Net 6

Implementation

WPF

Reproduction Steps

CefSharp.Wpf.Example is a good sample for learning how to use cefsharp in wpf.I noticed that NonReloadingTabControl was considered. There is no problem in CefSharp.Wpf.Example.However when I try to access NonReloadingTabControl with ReactiveUI-Mvvm,I encountered a issue.

The following codes for reference.

viewmode.cs:

 private readonly ReadOnlyObservableCollection<MockModel> _mocks;

 public MainWindowViewModel()
 {
      var mockLoadCacheCleanup = mockService.All.Connect()
                  .Transform(t => t)
                  .ObserveOn(schedulerProvider.MainThread)
                  .Bind(out _mocks)
                  .DisposeMany()
                  .Subscribe();
 }

 public ReadOnlyObservableCollection<MockModel> Mocks => _mocks;

view.xaml:

<theme:NonReloadingTabControl
                           HorizontalContentAlignment="Left"
                           BorderBrush="#333333"
                           BorderThickness="0"
                           ItemsSource="{Binding Mocks}"/>

When I add the first MockModel to _mocks,The NonReloadingTabControl just show the TabItem-Header,the TabItem-Content was collapsed.

I looked into the code in NonReloadingTabControl.cs
The first adding to _mocks triggered OnItemsChanged of NonReloadingTabControl,And the e.Action is Reset.So the itemsHolderPanel.Children.Clear(); was called.

protected override void OnItemsChanged(NotifyCollectionChangedEventArgs e)
{
           base.OnItemsChanged(e);

           if (itemsHolderPanel == null)
           {
               return;
           }

           switch (e.Action)
           {
               case NotifyCollectionChangedAction.Reset:
                   **itemsHolderPanel.Children.Clear();**
                   break;

Actually, this is not the issue of CefSharp.But if it can be fixed, it will give developers better guidance.

Expected behavior

When the Firstly adding to ReadOnlyObservableCollection,The TabControl can show header and content normally.

Actual behavior

When the Firstly adding to ReadOnlyObservableCollection,The TabControl show header only,content is missed.

Regression?

No response

Known Workarounds

Currently,I go with a workaround that delete switch (e.Action) code block.Reserve base.OnItemsChanged(e); only.
Hostly, removing the overriding to OnItemsChanged will work as well.

Does this problem also occur in the CEF Sample Application

Yes using WPF/OffScreen command line args

Other information

No response

[amaitland]

Converted to discussion as this isn't a bug in CefSharp.

Actually, this is not the issue of CefSharp.But if it can be fixed, it will give developers better guidance.

As per the xml doc NonReloadingTabControl was adapted from http://stackoverflow.com/a/9802346

It's not something that was created as part of this project. I'm not sure what's required to support other frameworks like ReactiveUI-Mvvm. Trying to provide generic support for a control that is provided purely as part of an example isn't really practical. There's no way to test or debug other frameworks.

I haven't searched for other alternative solutions in a long time, there are likely others. For reference see #3862 (comment)

If someone wants to create (or knows of) an open source project that provides a non virtualising tab control then I'm happy to switch the example to using that.