Have XamGrid with 1 bound column, 3 unbound columns

 for example: Product, UnitPrice, Quantity, Total

As the user enters quantity the Total has to get updated.

When the screen comes it has 10 rows with 10 products, unitprice filled in, and quantity and total are empty

Please give me a sample how to achieve this. total shouls get updated as user moves along the quantity column.

<ig:XamGrid Name="xg1">

<ig:TextColumn Key="Producutde" HeaderText="Producut"/>
<ig:UnboundColumn HeaderText="Unit Price" Key="UnitPrice" >
    <ig:UnboundColumn.ItemTemplate>
        <DataTemplate>
            <TextBox x:Name="UnitPrice"  />
        </DataTemplate>
    </ig:UnboundColumn.ItemTemplate>
</ig:UnboundColumn>
..similar to Quantity and Total

 Need the xaml and c# code for this