WPF Databinding to the "Selected Item"

[Nate Bross]

If you have a situation where you need to have a list of "items" and then populate fields outside the list with information from the selected item, this is for you.

 

Basic Concept

Set the DataContext of a parent container control, and Databind "Up the tree."

 

Example

<Window.Resources>
<ObjectDataProvider x:Key="myList" ObjectType="{x:Type YourCollection}" />
</Window.Resources>
<Grid x:Name="mainGrid" DataContext="{Binding Source={StaticResource myList}}">
   <ListBox IsSynchronizedWithCurrentItem="True" ItemsSource="{Binding}">
       // Your DataTemplate here
   </ListBox>
   <TextBlock Text="{Binding Path=/PropertyOfCollectionItem}" />
</Grid>

 

The key to note here is the /Item notation in the Binding of the items outside the list, and the IsSynchronizedWithCurrentItem="True" in the ListBox, and the ItemsSource="{Binding}" which says to "look up the tree" for a binding source.

 

What this does is make sure your bindings change with selected item changed.