ElementName bindings don't work inside ItemsRepeater DataTemplate

[JohnnyWestlake]

Describe the bug
As described, using ElementName bindings inside the datatemplate of an Items Repeater appears to fail. The same template inside anything that inherits ItemsControl works fine.

Steps to reproduce the bug

Steps to reproduce the behavior:

1. Create an ItemsRepeater
2. Inside it's DataTemplate, use an elementname binding to something outside of the ItemsRepeaters VisualTree.
3. Observe infinite nothingness

Expected behavior
It works.

Version Info
O.S. 18362.53
MinVersion SDK: 17134
MaxVersion SDK: 17763

NuGet package version:
2.1.190405004

[JohnnyWestlake]

Is there any follow up on this? Almost 2 years later and it seems like a pretty big thing to be missing, especially if we want ItemsRepeater to replace ListView/GridView, where it works fine.

[crodeheaver]

I'm also running into the same issue. Are there any work arounds for the issue?

[LanceMcCarthy]

@jevansaks I can confirm this bug is still present. I've tried both ElementName and RelativeSource bindings, nothing seems to be able to change the DataContext of that binding as long as it's inside the DataTemplate.

[jevansaks]

I'm sorry to hear that. @RealTommyKlein @ranjeshj any ideas?

[agneszitte]

I'm also running into the same issue even with the latest versions.
(cc @michael-hawker)

[michael-hawker]

This is a pain see folks hit trying to implement MVVM patterns. This effects both WinUI 2 and WinUI 3.

Someone recently created a nice isolated repro of the ItemsControl/ItemsRepeater difference here on one of our bugs, thanks to @leoshusar:

<ItemsControl ItemsSource="{x:Bind ViewModel.Items}">
    <ItemsControl.ItemTemplate>
        <DataTemplate x:DataType="x:String">
            <ComboBox Name="cmbTest1">
                <ComboBoxItem Content="TextBlock" Tag="TextBlock" />
                <ComboBoxItem Content="HyperLink" Tag="HyperLink" />
                <i:Interaction.Behaviors>
                    <ic:EventTriggerBehavior EventName="SelectionChanged">
                        <ic:EventTriggerBehavior.Actions>
                            <ic:InvokeCommandAction Command="{Binding ElementName=PageRoot, Path=ViewModel.Test1Command}" CommandParameter="{Binding ElementName=cmbTest1}" />
                        </ic:EventTriggerBehavior.Actions>
                    </ic:EventTriggerBehavior>
                </i:Interaction.Behaviors>
            </ComboBox>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

<ItemsRepeater Grid.Column="1" ItemsSource="{x:Bind ViewModel.Items}">
    <ItemsRepeater.ItemTemplate>
        <DataTemplate x:DataType="x:String">
            <ComboBox Name="cmbTest2">
                <ComboBoxItem Content="TextBlock" Tag="TextBlock" />
                <ComboBoxItem Content="HyperLink" Tag="HyperLink" />
                <i:Interaction.Behaviors>
                    <ic:EventTriggerBehavior EventName="SelectionChanged">
                        <ic:EventTriggerBehavior.Actions>
                            <ic:InvokeCommandAction Command="{Binding ElementName=PageRoot, Path=ViewModel.Test2Command}" CommandParameter="{Binding ElementName=cmbTest2}" />
                        </ic:EventTriggerBehavior.Actions>
                    </ic:EventTriggerBehavior>
                </i:Interaction.Behaviors>
            </ComboBox>
        </DataTemplate>
    </ItemsRepeater.ItemTemplate>
</ItemsRepeater>

Recording.2023-06-19.011441.mp4

App22.zip

FYI @bpulliam