Question

The SelectedItemChanged event and SelectedItem property of TreeView do not occur when the TreeViewItem is an input control like Textbox. The sample code below illustrates the problem by placing a breakpoint in TreeView SelectedItemChanged event. This breakpoint will fire when “String Header” is selected, but not “Textbox Header”.

I assume that the Textbox or RichTextbox (My real application) is eating some vital bubbling event. How can I get the TreeView SelectedItem to behave for a TextBox as it would for control like Label?

Note: If I can solve this issue I will need to two-way bind to SelectedItem as I am using MVVM and MEF. SelectedItem is readonly which is problem, which I plan to solve with ( http://silverscratch.blogspot.com/2010/11/two-way-binding-on-treeviewselecteditem.html ). I thought this related link might help someone.

XAML:

<TreeView SelectedItemChanged="TreeView_SelectedItemChanged">
    <TreeViewItem>
        <TreeViewItem.Header>
            <TextBox>
                Textbox Header
            </TextBox>
        </TreeViewItem.Header>
    </TreeViewItem>
    <TreeViewItem>
        <TreeViewItem.Header>
            String Header
        </TreeViewItem.Header>
    </TreeViewItem>
</TreeView>

Code Behind:

    private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
    {
        // Breakpoint will fire when "String Header" Selected
        // !!! Breakpoint does not fire when Textbox Selected
        var newValue = e.NewValue;
        var oldValue = e.OldValue;
    }

Thanks,

Answer 1

You should catch GotFocus event on your TreeView :

<TreeView SelectedItemChanged="TreeView_SelectedItemChanged"
          GotFocus="UIElement_OnGotFocus">
   <TreeViewItem>
      <TreeViewItem.Header>
          <TextBox>Textbox Header</TextBox>
       </TreeViewItem.Header>
   </TreeViewItem>
   <TreeViewItem>
        <TreeViewItem.Header>String Header</TreeViewItem.Header>
   </TreeViewItem>
 </TreeView>

private void UIElement_OnGotFocus(object sender, RoutedEventArgs e)
{
    TreeViewItem item = UIHelpers.TryFindParent<TreeViewItem>   
                           ((DependencyObject) e.OriginalSource);
    if (item != null)
          item.IsSelected = true;
}

The implementation of TryFindParent you may found here:
https://stackoverflow.com/a/4838168/1088908