WPF

<data:DataGrid Name="ParentDG" AutoGenerateColumns="False" RowDetailsVisibilityMode="VisibleWhenSelected">
    <data:DataGrid.Columns>
        <data:DataGridTextColumn Header="<<ColumnInfo>>" Binding="{Binding <<BindingInfo>>}" IsReadOnly="True" />
        ... 
    </data:DataGrid.Columns>
    <data:DataGrid.RowDetailsTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
                <data:DataGrid Name="NestedDG"></data:DataGrid>
            </StackPanel>
        </DataTemplate>
    </data:DataGrid.RowDetailsTemplate>
</data:DataGrid>

void ParentDG_RowDetailsVisibilityChanged(object sender, DataGridRowDetailsEventArgs e)
    {
       DataGrid nestedGrid = (DataGrid)e.DetailsElement.FindName("NestedDG");
       if (e.Row.DetailsVisibility == Visibility.Visible)
       {
           nestedGrid.ItemsSource = <<Set the item source for the nested grid here>>;
       }
   }

<br />
        <StackPanel Name="pnFreeTxt" Grid.Row="0" Grid.Column="0" VerticalAlignment="Top" Visibility="Collapsed"><br />
            <TextBox Name="SomeTextValues" Width="150px" GotFocus="SomeTextValues_GotFocus" PreviewMouseUp="SomeTextValues_PreviewMouseUp"></TextBox><br />
        </StackPanel><br />
        <br />
        private void SomeTextValues_GotFocus(object sender, RoutedEventArgs e)<br />
        {<br />
            base.OnGotFocus(e);<br />
            SomeTextValues.CaretIndex = FreeTextValues.Text.Length + 2;<br />
            return;<br />
        }<br />
<br />
        private void SomeTextValues_PreviewMouseUp(object sender, MouseButtonEventArgs e)<br />
        {<br />
            SomeTextValues.CaretIndex = FreeTextValues.Text.Length + 2;<br />
            SomeTextValues.ReleaseMouseCapture();<br />
            e.Handled = true;<br />
            return;<br />
        }<br />