+2  A: 
<ContentControl>
        <ContentControl.Style>
            <Style TargetType="ContentControl">
                <Setter Property="ContentControl.Template"  Value="{StaticResource Dock}"/>
                <Style.Triggers>
                    <DataTrigger Binding="{Binding IsDocked}" Value="False">
                        <Setter Property="ContentControl.Template"  Value="{StaticResource UnDock}"/>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </ContentControl.Style>
    </ContentControl>
Ragunathan
It worked.Thanks
suman