How I can find MouseClick or GotFocus event in PivotItem.?

Hello How I can find GotFocus event into the PivotItem I had tired with GalaSoft Interaction with Triger and EventName="GotFocus" but it is not fired can anybody help me to find the PivioItem Event.

Thank you.

the pivot item gets focus upon cliking any control placed inside that pivot item.

<controls:PivotItem Header="item1">
                <i:Interaction.Triggers>
                    <i:EventTrigger EventName="GotFocus">
                        <i:InvokeCommandAction Command="{Binding ShowMessageCommand}" />
                    </i:EventTrigger>
                </i:Interaction.Triggers>
                <Grid>
                    <TextBox Height="100"
                             Width="200"/>
                    <Button Height="100"
                            Width="200" />
                </Grid>
            </controls:PivotItem>

This code works for me. the pivot item get focus upon clicking the button or the text box. Hope this helps you.