title: How to Sort DataGridTemplateColumn (which uses MultiBinding), in the same order as the Multibound fields
body: <p>I have a custom entity, which contains FirstName, LastName properties (it has other properties also). I bind this entity to a datagrid, which displays FullName (LastName, FirstName) as a DataGridTemplateColumn (using MultiBinding with StringFormat). Users are allowed to sort datagrid columns and when they click on FullName columns, records must be sorted by LastName and then FirstName (sort direction will toggle based on the number of clicks). I would like to know if it is possible to achieve the desired sorting (multi column) in the above scenario? </p>
  
  <p>I tried using SortMemberPath attribute but there I can specify only one column. </p>
  
  <p>I Know if I add a custom ReadOnly property named FullName to my entity things would work, but I just want to understand if it is possible to achieve the same with MultiBinding implemented.</p>
  
  <p>Thanks,
  Pankaj</p>