CODEWITHSUNDEEP
c#linqsorting
webdad3
webdad3

Reputation: 9080

how to sort an anonymous type without named columns

Building from this question: Trying to concatenate columns in LINQ

Now I want to sort:

var orderByIndexVal = Convert.ToInt32(Request["iSortCol_0"]);
var direction = Request["sSortDir_0"];

var gridInfo = 
    from leader in db.SchoolLdrAdminAccesses
        join emp in db.Employees
        on leader.ID equals emp.ID
        select new List<string> { leader.ID, emp.FirstName + " " + emp.LastName };

 return Json(new
        {
           sEcho = param.sEcho,
           iTotalRecords = gridInfo.Count(),
           iTotalDisplayRecords = gridInfo.Count(),
           aaData = gridInfo.ToArray()
         },
         JsonRequestBehavior.AllowGet);

After reading this post: LINQ sorting anonymous types?

My issue is that I don't have anything named in my gridInfo

What I've tried so far:

            if (direction == "asc")
            {
                gridInfo =  gridInfo.OrderBy(gi => gi[orderByIndexVal]);
            }
            else
            {
                gridInfo = gridInfo.OrderByDescending(gi => gi[orderByIndexVal]);
            }

But I'm getting the following error:

LINQ to Entities does not recognize the method 'System.String get_Item(Int32)' method, and this method cannot be translated into a store expression.

On the following block of code:

            return Json(new
            {
                sEcho = param.sEcho,
                iTotalRecords = gridInfo.Count(),
                iTotalDisplayRecords = gridInfo.Count(),
                aaData = gridInfo.ToArray()
            },
            JsonRequestBehavior.AllowGet);

Upvotes: 0

Views: 176

Answers (2)

Diego
Diego

Reputation: 18359

You need to materialize the list, so the order by doesn't happen in the DB, but in .NET, after the concatenation takes place.

var gridInfo = (from leader in db.SchoolLdrAdminAccesses
        join emp in db.Employees
        on leader.ID equals emp.ID
        select new string[]{ leader.ID.ToString(), 
             emp.FirstName + " " + emp.LastName })
        .ToList();

Also note that using an array instead of a list uses less memory. Hope that helps.

Upvotes: 3

Tom Brown
Tom Brown

Reputation: 793

I think this is the problem 

new List<string> { leader.ID, emp.FirstName + " " + emp.LastName };

the anonymous type you are selecting is two columns { Int, String } not a simple List

Just Select new { leader.ID, emp.FirstName + " " + emp.LastName }; the Select statement will make it an IEnumerable automatically, so you don;t need the List<> part

I am assuming leader.ID is an Int here (which may be wrong)

Upvotes: 0

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