Question

I’m trying to create a Window with a ListView and an Area where details to the selected Object are displayed. The Listview displays items stored in an ObservableCollection(Of T) Collection. The items itself contain also an ObservableCollecton(Of T) Collection which should then be displayed in the details area in another ListView, accordingly to the selected item of the first ListView.

The Problem:
The InitializeComponent() throws an Exception (XAMLParseException).

Exception:
Set property 'System.Windows.Controls.GridViewColumn.DisplayMemberBinding' threw an exception.

InnerException:
Object of type 'System.String' cannot be converted to type 'System.Windows.Data.BindingBase'.

The Line- and ColumNumer of the Exception are Pointing at the <GridView> of my ListView (.View)

This is the First ListView

<ListView ItemsSource="{Binding Path=MyObjectCollection, Mode=OneWay}" SelectedItem="{Binding Path=Selected, Mode=OneWayToSource}">
   <ListView.View>
      <GridView>
         <GridViewColumn DisplayMemberBinding="{Binding Path=Name, Mode=OneWay}">
            <GridViewColumnHeader Content="Name" />
         </GridViewColumn>
      </GridView>
   </ListView.View>
</ListView>

And this is the second ListView

<ListView ItemsSource="{Binding Path=SelectedItem.MySubCollection, Mode=OneWay}">
   <ListView.View>
      <GridView> <!-- Thats the Line where the Exception is pointing at -->
         <GridViewColumn Width="150" DisplayMemberBinding="Key">
            <GridViewColumnHeader Content="Key" />
         </GridViewColumn>
         <GridViewColumn Width="150" DisplayMemberBinding="Value">
            <GridViewColumnHeader Content="Value" />
         </GridViewColumn>
      </GridView>
   </ListView.View>
</ListView>

So. How can I bind to the Collection Property of an Object could be nothing?

Answer 1

From the exception message the problem is with with your DisplayMemberBinding in the second listview. Because you have to provide a Binding expression instead of a string see MSDN. Like in your first listview:

<ListView ItemsSource="{Binding Path=SelectedItem.MySubCollection, Mode=OneWay}">
   <ListView.View>
      <GridView> <!-- Thats the Line where the Exception is pointing at -->
         <GridViewColumn Width="150" DisplayMemberBinding="{Binding Path=Key}">
            <GridViewColumnHeader Content="Key" />
         </GridViewColumn>
         <GridViewColumn Width="150" DisplayMemberBinding="{Binding Path=Value}">
            <GridViewColumnHeader Content="Value" />
         </GridViewColumn>
      </GridView>
   </ListView.View>
</ListView>