Question

I have a DataTemplate that will be a templated ListBoxItem, this DataTemplate has a
ComboBox in it which when it has focus I want the ListBoxItem that this template
represents to become selected, this looks right to me. but sadly enough it doesn’t work =(

So the real question here is within a DataTemplate is it possible to get or set the value
of the ListBoxItem.IsSelected property via a DataTemplate.Trigger?

<DataTemplate x:Key="myDataTemplate" 
              DataType="{x:Type local:myTemplateItem}">

 <Grid x:Name="_LayoutRoot">
     <ComboBox x:Name="testComboBox" />
 </Grid>

 <DataTemplate.Triggers>
     <Trigger Property="IsFocused" value="true" SourceName="testComboBox">
         <Setter Property="ListBoxItem.IsSelected" Value="true" />
     </Trigger>
 </DataTemplate.Triggers>

</DataTemplate>

<ListBox ItemTemplate="{StaticResource myDataTemplate}" />

Answer 1

I found a solution for your problem.

The problem is that when you have a control on your listboxitem, and the control is clicked (like for inputting text or changing the value of a combobox), the ListBoxItem does not get selected.

this should do the job:

public class FocusableListBox : ListBox
{
    protected override bool IsItemItsOwnContainerOverride(object item)
    {
        return (item is FocusableListBoxItem);
    }

    protected override System.Windows.DependencyObject GetContainerForItemOverride()
    {
        return new FocusableListBoxItem();
    }
}

–> Use this FocusableListBox in stead of the default ListBox of WPF.

And use this ListBoxItem:

public class FocusableListBoxItem : ListBoxItem
{
    public FocusableListBoxItem()
    {
        GotFocus += new RoutedEventHandler(FocusableListBoxItem_GotFocus);
    }


    void FocusableListBoxItem_GotFocus(object sender, RoutedEventArgs e)
    {
        object obj = ParentListBox.ItemContainerGenerator.ItemFromContainer(this);
        ParentListBox.SelectedItem = obj;
    }

    private ListBox ParentListBox
    {
        get
        {
            return (ItemsControl.ItemsControlFromItemContainer(this) as ListBox);
        }
    }

}

A Treeview does also have this problem, but this solution does not work for a Treeview, ’cause SelectedItem of Treeview is readonly.
So if you can help me out with the Treeview please 😉