WPF DataTemplate Access Childs

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C#

.NET

WPF

DataTemplate

Hi Experts,

I have a Problem accessing a Listbox which is defined in a datatemplate. Here is my XAML:

<Grid>
       <TabControl Name="tbCategories" Height="200" AllowDrop="True" VerticalAlignment="Top" HorizontalAlignment="Stretch" Grid.Column="1" ItemsSource="{Binding}" SelectionChanged="tbCategories_SelectionChanged">
           <TabControl.ItemTemplate>
               <DataTemplate>
                   <StackPanel Orientation="Horizontal" Margin="0" Name="spHeader">
                       <Grid Name="gdHeader">
                           <TextBox Name="tbCategoryNameEdit"  LostFocus="tbCategoryNameEdit_LostFocus" Text="{Binding Name}" removed="Transparent" BorderThickness="0" Visibility="Collapsed"/>
                           <TextBlock Name="tbCategoryName" MouseLeftButtonDown="tbCategoryName_MouseLeftButtonDown" Text="{Binding Name}" removed="Transparent" Visibility="Visible"/>
                       </Grid>
                       <Button Name="butDelete" Visibility="{Binding CanDelete, Converter={StaticResource boolvisibilityconverter}}" Content="x" VerticalContentAlignment="Center" Click="butDelete_Click" HorizontalContentAlignment="Center" Height="10" Width="10" FontSize="7" HorizontalAlignment="Right" VerticalAlignment="Top" Background="Transparent" BorderThickness="0" />
                   </StackPanel>
               </DataTemplate>
           </TabControl.ItemTemplate>

           <TabControl.ContentTemplate>
               <DataTemplate>
                   <ListBox AllowDrop="True" KeyDown="lbTemplates_KeyDown" ItemsSource="{Binding Templates}" BorderThickness="0" x:Name="lbTemplates" MouseDoubleClick="lbTemplates_MouseDoubleClick">
                       <ListBox.ContextMenu>
                           <ContextMenu>
                               <MenuItem Header="Copy" Name="mnuCopy" Click="mnuCopy_Click" />
                               <MenuItem Header="Paste" Name="mnuPaste" Click="mnuPaste_Click" />
                           </ContextMenu>
                       </ListBox.ContextMenu>
                   </ListBox>
               </DataTemplate>
           </TabControl.ContentTemplate>
       </TabControl>
   </Grid>

What i want to do is get the selected Listbox Item when Clicking the ContextMenu Copy Item:
I thought this line of code should manage all for me and should return me the Listbox of the current selected TabItem:

tbCategories.SelectedContentTemplate.FindName("lbTemplates", tbCategories);

When I am calling FindName I get an InvalidOperationException?
Does anyone have an idea what I am doing wrong?

KR and Thanks
Manu