How to expand WPF TreeView on single click of item

Question

Right now you have to double click or click the + icon. Is there any way to make it so if a user clicks anywhere on the node it expands?

Answer 1

I had this same problem and found a good solution thanks to another StackOverflow post.

In the control.xaml's TreeView element, you can hook directly into the TreeViewItem's Selected event:

<TreeView ItemsSource="{StaticResource Array}" TreeViewItem.Selected="TreeViewItem_Selected"/>

Then in your control.xaml.cs code behind, you can grab that selected TreeViewItem from the RoutedEventArgs and set it to IsExpanded:

private void TreeViewItem_Selected(object sender, RoutedEventArgs e)
{
    TreeViewItem tvi = e.OriginalSource as TreeViewItem;

    if (tvi == null || e.Handled) return;

    tvi.IsExpanded = !tvi.IsExpanded;
    e.Handled = true;
}

Nice and clean. Hopefully that helps someone!

Answer 2

Maybe is not the most elegant solution but this works:

    static DependencyObject VisualUpwardSearch<T>(DependencyObject source)
    {
        while (source != null && source.GetType() != typeof(T))
            source = VisualTreeHelper.GetParent(source);

        return source;
    }

then in the TreeViewItem.Selected Handler:

        private void Treeview_Selected(object sender, RoutedEventArgs e)
        {
            var treeViewItem = VisualUpwardSearch<TreeViewItem>(e.OriginalSource as DependencyObject) as TreeViewItem;
            if (treeViewItem != null) treeViewItem.IsExpanded = true;
        }

the VisualUpwardSearch magic is taken from here: Select TreeView Node on right click before displaying ContextMenu

Regards