Question

I think my question is rather basic, but I can’t find an answer:
I have a TreeView, and I can’t figure out how to monitor nodes’ selection. I have breakpoints at the handlers for both TreeView.SelectedItemChanged and TreeViewItem.Expanded. When a node is expanded I do see the TreeViewItem.Expanded handler at work, but when clicking on a node, none of those events are fired.
What am I doing wrong?

Thanks.

TreeView code:

    <TreeView Name="TestsTree" Height="Auto" MinHeight="50" ItemsSource="{Binding Path=TreeNodes, Mode=TwoWay}" TreeViewItem.Expanded="TestsTreeExpanded" TreeView.SelectedItemChanged="TestsTreeSelectedItemChanged">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Path=TreeNodes, Mode=TwoWay}" DataType="{x:Type TestExplorer:FolderTreeNode}">
                <TreeViewItem Header="{Binding Name}"/>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
        </TreeView>

Edit:
I’ve tried using TreeViewItem.Selected but it’s the same – when I click on a node’s name there’s no reaction, though when I click at the expansion area, both TreeViewItem.Selected and TreeViewItem.Selected are fired. Any explanation?

Answer 1

You shouldn’t put a TreeViewItem in your DataTemplate. The TreeViewItem is created automatically by the TreeView. The DataTemplate defines the content of the TreeViewItem, not the TreeViewItem itself. Now you have two nested TreeViewItems, which is probably why it doesn’t work as expected. Try that instead:

        <HierarchicalDataTemplate ItemsSource="{Binding Path=TreeNodes, Mode=TwoWay}" DataType="{x:Type TestExplorer:FolderTreeNode}">
            <TextBlock Text="{Binding Name}"/>
        </HierarchicalDataTemplate>