LINQ to Entities does not recognize my method

Question

I want to convert date and time to Persian in LINQ select but linq can not recognize my method :

LINQ to Entities does not recognize the method \'

Answer 1

EF cannot translate your custom method to SQL. You can inject a .AsEnumerable() call to change the underlying context from EF to Linq-to-Objects:

var result = (from ord in db.vw_orders
              where ord.uid == user.id
              orderby ord.order_date descending select ord
             )
             .AsEnumerable()
             .Select(o => new { o.id,
                                date = Tools.toPersianDateTime((DateTime)o.order_date),
                                o.is_final, 
                                o.status, 
                                o.image_count, 
                                o.order_count, 
                                o.total_price }
                    );