Disable WPF TreeView (or TreeViewItem) selection?

Try this:

<Trigger Property="HasItems" Value="true">
   <Setter Property="Focusable" Value="false" />
</Trigger>

Based off of the links to the currently accepted answer, I implemented this in my project:

<ListView.ItemContainerStyle>
    <Style TargetType="{x:Type ListViewItem}">
        <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
    </Style>
</ListView.ItemContainerStyle>

Works for TreeViewItem as well. And in the view model:

protected bool _DisableSelection;
private bool _IsSelected;
public bool IsSelected
{
    get { return _IsSelected; }
    set
    {
        if (value == _IsSelected) return;
        _IsSelected = _DisableSelection ? false : value;
        NotifyPropertyChanged();
    }
}

Now you don't have to go hunting!

This did the trick for me (based on this answer, but no tied to item - selection is disabled whatsoever):

<TreeView>
  <TreeView.ItemContainerStyle>
    <Style TargetType="TreeViewItem">
      <Setter Property="Focusable" Value="False" />
    </Style>
  </TreeView.ItemContainerStyle>
</TreeView>