Editable WPF treeview item on doubleclick? (with styles?)

Question

Hi - I'm a bit of a WPF noob, so apologies for any inherent daftness in this question (!)

I'm trying to enable editing of WPF treeview labels with a doubleclick - I've googled around this, and it looks like the two ways of doing this are with a custom control or with a style which hides one of a TextBox/TextBlock.

Using a style to set the label to be a textBox based on a DataTrigger seems easy enough (eg 1 below), but it means that any time a row is selected, it's 'being edited'.

What I'd really like to do is to enable this (Transition to textbox) on a mousedoubleclick event, but it seems that EventTriggers can't be used in the manner below, because they're transient. (It doesn't seem I can simply use the DoubleClick event in codebehind, because that doesn't (??) allow me to affect the displayed controls to show / hide the textboxes).

Using a full blown custom control seems like the alternative - there's an AAALMOST working example here ( http://www.codeproject.com/KB/WPF/editabletextblock.aspx ), however it doesn't work in the presence of HierachicalDataTemplate clauses (and it doesn't look like a solution is forthcoming).

Any ideas?

Many thanks.

Lee.

(eg 1 - switch from textblock to textbox when selected)

<Window x:Class="treetest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:treetest"
Title="Window1" Height="300" Width="300">
<Window.Resources>
    <Style x:Key="EditableContentControl" TargetType="{x:Type ContentControl}">
        <Setter Property="ContentTemplate">
            <Setter.Value>
                <DataTemplate DataType="{x:Type local:CompositeViewModel}">
                    <TextBlock Text="{Binding Path=Name}" />
                </DataTemplate>
            </Setter.Value>
        </Setter>
        <Style.Triggers>
            <DataTrigger Binding="{Binding Path=IsSelected,RelativeSource=RelativeSource AncestorType={x:Type TreeViewItem}}}"
                 Value="True">
                <Setter Property="ContentTemplate">
                    <Setter.Value>
                        <DataTemplate DataType="{x:Type local:CompositeViewModel}">
                            <TextBox Text="{Binding Path=Name,UpdateSourceTrigger=PropertyChanged}" />
                        </DataTemplate>
                    </Setter.Value>
                </Setter>                
            </DataTrigger> 
        </Style.Triggers>
    </Style>  
</Window.Resources>
<Grid>
    <TreeView Margin="12,12,115,12" Name="treeView1"  
              ItemsSource="{Binding Path=GetRootData}"
              >
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate DataType="{x:Type local:CompositeViewModel}" ItemsSource="{Binding Path=Children}">
                <ContentControl Content="{Binding}" Style="{StaticResource EditableContentControl}"/>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>
</Grid>
</Window>