Por que o LINQ to Entities não reconhece o método 'System.String ToString ()?

Obtendo erro dentro do aplicativo da web MVC3.LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression.

quando eu tento buscar valores usando EF da consulta:

<code>public class DataRepository
    {
        public mydataEntities1 dbContext = new mydataEntities1();

        public List<SelectListItem> GetPricingSecurityID()
        {
        var pricingSecurityID = (from m in dbContext.Reporting_DailyNAV_Pricing
                                     select new SelectListItem
                                         {
                                                Text = m.PricingSecurityID.ToString(),
                                                Value = m.PricingSecurityID.ToString()
                                         });

        return pricingSecurityID.ToList();
        }
    }
</code>

questionAnswers(7)

yourAnswerToTheQuestion