C# – LINQ to Entities does not recognize the method ‘System.String ToString()’ method MVC3

asp.net-mvc-3cvisual studio 2012

Error Description: LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression.

The error comes up while executing following code:

public ActionResult NewBooking()
    {
        var db = new VirtualTicketsDBEntities2();

        IEnumerable<SelectListItem> items = db.Attractions
          .Select(c => new SelectListItem
          {
              Value = c.A_ID.ToString(),
              Text = c.Name
          });
        ViewBag.CategoryID = items;
        return View();
    }

Any suggestion to get rid of this error?

Thanks.

Best Answer

You can use an AsEnumerable() to change the binding context from Linq-to-Entities to Linq-to-Objects:

IEnumerable<SelectListItem> items = db.Attractions
    .AsEnumerable()
    .Select(c => new SelectListItem
    {
        Value = c.A_ID.ToString(),
        Text = c.Name
    });

Related Solutions

C# – LINQ to Entities does not recognize the method ‘System.String ToString()’ method, and this method cannot be translated into a store expression

Just save the string to a temp variable and then use that in your expression:

var strItem = item.Key.ToString();

IQueryable<entity> pages = from p in context.pages
                           where  p.Serial == strItem
                           select p;

The problem arises because ToString() isn't really executed, it is turned into a MethodGroup and then parsed and translated to SQL. Since there is no ToString() equivalent, the expression fails.

Note:

Make sure you also check out Alex's answer regarding the SqlFunctions helper class that was added later. In many cases it can eliminate the need for the temporary variable.

C# – LINQ to Entities does not recognize the method ‘System.String ToString()’ method and this method cannot be translated into a store expression

I would suggest fetching the title and the brand in an anonymous type, and then performing the string concatenation in-process:

var list = db.Brand.Where(c => c.Title.Contains("test"))
                   .Select(c => new { c.Title, c.Brand })
                   .AsEnumerable() // Rest of the query in-process
                   .Select(x => x.Title + " " + x.Brand)
                   .ToList();

Best Answer

Related Solutions

C# – LINQ to Entities does not recognize the method ‘System.String ToString()’ method, and this method cannot be translated into a store expression

Note:

C# – LINQ to Entities does not recognize the method ‘System.String ToString()’ method and this method cannot be translated into a store expression

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