how to bind width of child element to width of parent element in silverlight

Question

I have a grid whose width is "1*". So the actual width decided at runtime I think. Within that grid I have another grid whose width I want to set to the runtime width of parent grid. How Can I do that in xaml through binding.

Answer 1

This will actually help you I guess

Width="{Binding ActualWidth, ElementName=parentElementName}"

This binds the width to the parent element or the element name provided

Answer 2

This is generic solution which may work everywhere. You wouldn't need to write parent element name. This will identify its parent and will take parent's width.

Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=ActualWidth}"

Answer 3

I think that easiest way to do same thing is:

HorizontalAlignment="Stretch"

That is not using binding as you have been asked, but it is easier.

Answer 4

If you are doing it in CodeBehind, this works for me. It has the added advantage that bindMe does not have to be a child of toMe:

public static void BindWidth(this FrameworkElement bindMe, FrameworkElement toMe)
{
  Binding b = new Binding();
  b.Mode = BindingMode.OneWay;
  b.Source = toMe.ActualWidth;
  bindMe.SetBinding(FrameworkElement.WidthProperty, b);
}

usage:

child.BindWidth(parent);

Answer 5

 Width="{Binding Width, RelativeSource={RelativeSource AncestorType={x:Type Parent}, Mode=FindAncestor}}"

if both controls DataContext is different.

Answer 6

If it is inside a Template use this:

<ListBox>
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Vertical">
                <Image Width="{TemplateBinding Width}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Source="TestImage.png"/>
                <TextBlock HorizontalAlignment="Center" Text="Test Text"/>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>