RelativeSource binding to a parent property of a ComboBox SelectedItem return object

Question

Hey all,

Given the data structure { Collection elements; String LocationName; }

And a ComboBox that is bound to a collection of such items (described in the structure) with DisplayMemberPath set to LocationName, how do I bind a datagrid to the SelectedItem.Elements of said combo box in XAML?

By my understanding the SelectedItem property of the combo box will return LocationName. I would need to move up in the data context of the structure then attach SourceItems to Elements. Correct? However I cannot seem to make it work with the Binding markup.

P.S. I am working on rigging a GUI with sample data.

Thank you.

Update 1: Code looks as follows:

<ComboBox x:Name="ComboBox1"
           ItemsSource="{Binding AdSources, Mode=OneWay}"
           DisplayMemberPath="NameProperty" />

<ComboBox x:Name="ComboBox2" 
               ItemsSource="{Binding SelectedItem.CollectionProperty, ElementName=ComboBox1, Mode=OneWay}"
               DisplayMemberPath="NameProperty2" />

<data:DataGrid x:Name="DataGrid"
        ItemsSource="{Binding SelectedItem.CollectionProperty, ElementName=ComboBox2, Mode=OneWay}">
      <data:DataGrid.Columns>
          <data:DataGridTextColumn Header="Column1" Binding="{Binding Property1}"/>
      </data:DataGrid.Columns>
</data:DataGrid>

Answer 1

The SelectedItem will point to the entire object, that's why you specified a DisplayMemberPath for LocationName. The entire object is selected, but only the location name is displayed.

You can bind to SelectedItem.Elements - if that doesn't work, your problem is somewhere else.