WPF TextBox focus through MVVM

gistfile1.xml

<Style x:Key="NormalTextBox" TargetType="{x:Type TextBox}">
    <Style.Triggers>
        <DataTrigger Binding="{Binding IsFocused}" Value="True">
            <Setter Property="FocusManager.FocusedElement" 
                Value="{Binding RelativeSource={RelativeSource Self}}" />
        </DataTrigger>
    </Style.Triggers>
</Style>

Good