Silverlight colonna combobox in Datagrid

Il seguente frammento di codice XAML, visualizza una colonna di tipo combobox, del controllo datagrid di Silverlight

<sdk:DataGrid AutoGenerateColumns="False" Grid.Column="1" Grid.ColumnSpan="7" Grid.Row="1" Height="311" HorizontalAlignment="Left" Margin="0,69,0,0" Name="DtgCombo" VerticalAlignment="Top" Width="965">

<sdk:DataGrid.Columns>

<sdk:DataGridTemplateColumn CanUserReorder="True" CanUserResize="True" CanUserSort="True" Header="Testo intestazione" Width="Auto" >

<sdk:DataGridTemplateColumn.CellTemplate>

<DataTemplate>

<ComboBox>

<ComboBoxItem Content="Testo A" />

<ComboBoxItem Content="Testo B" />

</ComboBox>

</DataTemplate>

</sdk:DataGridTemplateColumn.CellTemplate>

</sdk:DataGridTemplateColumn>

</sdk:DataGrid.Columns>

</sdk:DataGrid>