RadGrid: format double with eval

In order to format double with eval :

 <telerik:GridTemplateColumn HeaderText="Ortalama" DataField="Ortalama" UniqueName="Ortalama"  
                         SortExpression="Ortalama" HeaderStyle-Width="80px" >  
                         <ItemTemplate>  
                           <%# String.Format("{0:f2}", DataBinder.Eval(Container.DataItem, "Ortalama"))%>  
                         </ItemTemplate>  
                       </telerik:GridTemplateColumn>  

the solution is from: http://stackoverflow.com/questions/5168592/force-a-string-to-2-decimal-places