How to display underlying model data in tooltip?

<!—ToolTipTemplate for the series -->
<Grid.Resources>
    <DataTemplate x:Key="tooltipTemplate">
        <Border BorderBrush="Brown" BorderThickness="3">
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                </Grid.ColumnDefinitions>
                <StackPanel Background="PaleGreen" >
                    <TextBlock Text="Value : " Margin="5"  
                       VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="13" FontWeight="Bold"/>
                    <TextBlock Text="Text : " Margin="5" 
                       VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="13" FontWeight="Bold"/>
                </StackPanel>
                <StackPanel Background="PaleGreen" Grid.Column="1">
                    <TextBlock Text="{Binding YData,StringFormat=N}" Margin="5" 
                       VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="13" FontWeight="Bold"/>
                    <TextBlock Text="{Binding Item.Text}" Margin="5" 
                       VerticalAlignment="Center" HorizontalAlignment="Center" FontSize="13" FontWeight="Bold"/>
                </StackPanel>
            </Grid>
        </Border>
    </DataTemplate>
</Grid.Resources>
<!—Adding Chart -->
<chart:SfChart x:Name="chart" Margin="10" Header="Product Details" FontSize="18">
    <chart:SfChart.DataContext>
        <local:ViewModel/>
    </chart:SfChart.DataContext>
    <chart:SfChart.PrimaryAxis>
        <chart:CategoryAxis Header="Product ID"/>
    </chart:SfChart.PrimaryAxis>
    <chart:SfChart.SecondaryAxis>
        <chart:NumericalAxis Header="Value"/>
    </chart:SfChart.SecondaryAxis>
    <chart:ColumnSeries XBindingPath="ProdId" YBindingPath="Price" ItemsSource="{Binding Products}" TooltipTemplate="{StaticResource tooltipTemplate}" ShowTooltip="True" />
</chart:SfChart>

public MainWindow()
{
    InitializeComponent();
    GetSeries();
}
private void GetSeries()
{
    ColumnSeries series = new ColumnSeries();
    ViewModel obj = new ViewModel();
    series.ItemsSource = obj.Products;
    series.XBindingPath = "ProdId";
    series.YBindingPath = "Price";
    chart.Series.Add(series);
    series.ShowTooltip = true;
    series.TooltipTemplate = SetToolTipTemplate();
}
private DataTemplate SetToolTipTemplate()
{
    DataTemplate template = new DataTemplate();
    FrameworkElementFactory txtblock = new FrameworkElementFactory(typeof(TextBlock));
    txtblock.SetValue(TextBlock.WidthProperty, 85.0);
    txtblock.SetValue(TextBlock.HeightProperty, 25.0);
    txtblock.SetValue(TextBlock.VerticalAlignmentProperty, VerticalAlignment.Center);
    txtblock.SetValue(TextBlock.HorizontalAlignmentProperty, HorizontalAlignment.Center);
    txtblock.SetValue(TextBlock.FontSizeProperty, 15.0);
    Binding binding = new Binding();
    binding.Path = new PropertyPath("YData");
    txtblock.SetValue(TextBlock.TextProperty, binding);
    FrameworkElementFactory txtblock1 = new FrameworkElementFactory(typeof(TextBlock));
    txtblock1.SetValue(TextBlock.WidthProperty, 85.0);
    txtblock1.SetValue(TextBlock.HeightProperty, 25.0);
    txtblock1.SetValue(TextBlock.VerticalAlignmentProperty, VerticalAlignment.Center);
    txtblock1.SetValue(TextBlock.HorizontalAlignmentProperty, HorizontalAlignment.Center);
    Binding binding1 = new Binding();
    binding1.Path = new PropertyPath("Item.Text");//Gets the Price property value from Observable collection.
    txtblock1.SetValue(TextBlock.TextProperty, binding1);
    FrameworkElementFactory grid = new FrameworkElementFactory(typeof(StackPanel));
    grid.AppendChild(txtblock1);
    grid.AppendChild(txtblock);
    template.VisualTree = grid;
    return template;
}