Adding an icon to a treeviewitem element

Here is the code I have that is functionnal :

<TreeView SelectedItemChanged="item_Clicked" Grid.Column="0" Grid.Row="0" VerticalAlignment="Stretch">

     <TreeViewItem Header="Frame1" ItemsSource="{Binding Items}" IsExpanded="True">
         <TreeViewItem.ItemTemplate>
             <DataTemplate>
                 <TextBlock Text="{Binding Name}"/>
             </DataTemplate>
         </TreeViewItem.ItemTemplate>
     </TreeViewItem>
</TreeView>
开发者_如何学运维

the thing is that I'd like to add an icon to the root-node "Frame1" I tried a lot of things with StackPanel & TreeViewItem.Items, but I don't manage to do it... I want the icon to be between the "+" (that expands the node) and the Header (Frame1).

Thanks in anticipation for any help and sry for my english :(

---

Here is an example:

 <TreeViewItem ItemsSource="{Binding Items}" IsExpanded="True">
    <TreeViewItem.Header>
      <DockPanel>
          <Image DockPanel.Dock="Left" Width="20" />
          <TextBlock Text="Frame1" />
      </DockPanel>
    </TreeViewItem.Header>
     <TreeViewItem.ItemTemplate>
         <DataTemplate>
             <TextBlock Text="{Binding Name}"/>
         </DataTemplate>
     </TreeViewItem.ItemTemplate>
 </TreeViewItem>

I removed the SelectedItemChanged event for my brevity, so add it again.

Cheers