Изменение текста в TextBox элемента в GridView при клике мышью

  <DataTemplate>
                    <Grid HorizontalAlignment="Left" Width="250" Height="250">
                        <Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}">
                            <Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>
                        </Border>
                        <StackPanel VerticalAlignment="Top" Orientation="Horizontal" Background="{ThemeResource ListViewItemOverlayBackgroundThemeBrush}" HorizontalAlignment="Right">
                            <TextBlock Text="{Binding Content}" Margin="5,0,0,0" TextAlignment="Right" Foreground="{ThemeResource ListViewItemOverlayForegroundThemeBrush}" FontSize="36"/>
                            <TextBlock Text=" руб." Foreground="{ThemeResource ListViewItemOverlayForegroundThemeBrush}" FontSize="36" HorizontalAlignment="Right"/>
                        </StackPanel>
                        <StackPanel VerticalAlignment="Bottom" Background="{ThemeResource ListViewItemOverlayBackgroundThemeBrush}">
                            <TextBlock Text="{Binding Title}" Foreground="{ThemeResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextBlockStyle}" Height="60" Margin="15,0,15,0"/>
                            <TextBlock x:Name="kol" Text="{Binding Subtitle}" Foreground="{ThemeResource AppBarBackgroundThemeBrush}" Style="{StaticResource CaptionTextBlockStyle}" TextWrapping="NoWrap" Margin="15,-25,15,10"/>
                        </StackPanel>
                    </Grid>
                </DataTemplate>