ControlTemplate not propagating the BindingContext correctly

[ivan-todorov-progress]

Description

The bug manifests itself when using a ContentView with a custom ControlTemplate. For some reason, the BindingContext is not propagated to the children created with the ControlTemplate. This makes it impossible to use regular data binding in the ControlTemplate. For example, let's consider the following trivial scenario:

<VerticalStackLayout>
    <Label Text="{Binding Text}" />
    <ContentView>
        <ContentView.ControlTemplate>
            <ControlTemplate>
                <Label Text="{Binding Text}" />
            </ControlTemplate>
        </ContentView.ControlTemplate>
    </ContentView>
</VerticalStackLayout>

The first Label that is placed directly in the VerticalStackLayout displays the Text property form the BindingContext correctly. The second Label that is created from the ControlTemplate does not display anything at all.

Steps to Reproduce

1. Run the provided sample project
2. Observe the text of the two Labels

• The first Label displays the text correctly
• The second Label from the ControlTemplate is empty

Link to public reproduction project repository

https://github.com/ivan-todorov-progress/maui-control-template-binding-context-bug

Version with bug

7.0 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS, Android, Windows, macOS

Affected platform versions

N/A

Did you find any workaround?

The workaround is to propagate the BindingContext manually, e.g.:

<ControlTemplate>
    <Label Text="{Binding Text}" BindingContext="{Binding BindingContext, Source={RelativeSource Mode=TemplatedParent}}" />
</ControlTemplate>

Relevant log output

No response

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.