Setting tooltip of a control to the lastest error   

I am trying to figure out how to do the equivalent of the following in c#:

<Style x:Key=”tbStyle” TargetType=”{x:Type TextBox}”>
        <Style.Triggers>
            <Trigger Property=”Validation.HasError” Value=”true”>
                <Setter Property=”ToolTip”
                 Value=”{Binding RelativeSource={RelativeSource Self}, 
Path=(Validation.Errors)[0].ErrorContent}”/>
            </Trigger>
        </Style.Triggers>
    </Style>

Regards

date: Fri, 23 May 2008 23:14:00 -0700   author:   CoolAid am