Question

I’ve created a custom Control called EllipsisTextBlock with a DependencyProperty aiming to receive another Control’s property value:

public static readonly DependencyProperty CopyTextBlockWidthProperty =
        DependencyProperty.Register("CopyTextBlockWidth", typeof(double), typeof(EllipsisTextBlock),
        new PropertyMetadata(0d, null));

In the EllipsisTextBlock’s parent Grid, I’m binding the other Control’s property like this:

<Grid Margin="10,0,0,0" Grid.Column="1">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" MaxHeight="84"/>
            <RowDefinition Height="Auto" MaxHeight="72"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*" MaxHeight="120"/>
        </Grid.RowDefinitions>
        <TextBlock x:Name="tbxTeste" Text="{Binding Title}" FontSize="28" Visibility="Collapsed" Grid.Row="0"></TextBlock>
        <extensions:EllipsisTextBlock Text="{Binding Title}" FontSize="28" TextWrapping="Wrap" CopyTextBlockWidth="{Binding Path=ActualWidth, ElementName=tbxTeste}" Grid.Row="0"></extensions:EllipsisTextBlock>
...

What happens is that EllipsisTextBlock’s CopyTextBlockWidth property’s Set is never called:

public double CopyTextBlockWidth
    {
        get { return (double)GetValue(CopyTextBlockWidthProperty); }
        set { SetValue(CopyTextBlockWidthProperty, value); }
    }

By the way, EllipsisTextBlock class have two other DependencyProperties which works.

Any ideas?

Thanks

Answer 1

Although it is misleading using the XAML attribute syntax, SetBinding is called, not SetValue nor the CLR setter when you assign a binding to a property in XAML.