CODEWITHSUNDEEP
.netwpfxamlbinding
dotNET
dotNET

Reputation: 35400

Specifying multiple RelativeSource.AncestorTypes

Is there a easy hack for doing the following?

<Binding RelativeSource="{RelativeSource AncestorType=UserControl OR Window}" Path="Tag" />

I simply want to bind to the top-level parent's Tag property, which could either be UserControl or Window. Note however that the distance from the current control to the parent is arbitrary, so I can't use AncestorLevel.

Upvotes: 1

Views: 537

Answers (2)

bengr
bengr

Reputation: 313

You can just use MultiBinding instead of Binding for this, and then make a simple IMultiValueConverter that finds the first item in "values" that isn't null (or DependencyProperty.UnsetValue, which tends to pop up when working with the Visual Tree.

It's a less hacky way to do this, and works perfectly for me.

Upvotes: 0

Phil
Phil

Reputation: 42991

Well if it's a hack you want :)

public partial class MainWindow : ITopLevel
{
    public MainWindow()
    {
        InitializeComponent();

        Tag = "I'm at the top";
    }
}

public interface ITopLevel
{
    // optionally specify Tag in the interface, it will work either way
    object Tag { get; set; }
}

<Grid>
    <Button Content="{Binding Path=Tag, RelativeSource={RelativeSource 
            FindAncestor, AncestorType={x:Type Demo:ITopLevel}}}"/>
</Grid>

Upvotes: 3

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