JSON results are returned in a different order than expected

Question

I am following Phil Haack's example on using jQuery Grid with ASP.NET MVC. I have it working and it works well...except for one minor problem. When I sort the columns by something other than the ID, the JSON data returned from the server is very...well...wrong. Here's is my Controller method.

[HttpPost]
public ActionResult PeopleData(string sidx, string sord, int page, int rows)
{
    int pageIndex = Convert.ToInt32(page) - 1;
    int pageSize = rows;
    int totalRecords = repository.FindAllPeople().Count();
    int totalPages = (int)Math.Ceiling((float)totalRecords / (float)pageSize);

    var people = repository.FindAllPeople()
        .OrderBy(sidx + " " + sord)
        .Skip(pageIndex * pageSize)
        .Take(pageSize);

    var jsonData = new
    {
        total = totalPages,
        page = page,
        records = totalRecords,
        rows = (
            from person in people
            select new
            {
                i = person.PersonID,
                cell = new List<string> { SqlFunctions.StringConvert((double) person.PersonID), person.PersonName }
            }
        ).ToArray()
    };

    return Json(jsonData);
}

When I sort by PersonID in the jsGrid table, I get this data back (I just used the name of the current ID as the name - e.g. 1, One; 2, Two, etc.)

{"total":1,"page":1,"records":6,"rows":[{"i":1,"cell":[" 1","One"]},{"i":2,"cell":["         2","Two"]},{"i":3,"cell":["         3","Three"]},{"i":4,"cell":["         4","Four"]},{"i":5,"cell":["         5","Five"]},{"i":6,"cell":["         6","Six"]}]}

When I sort by PersonName, however, every other row has the order (the ID vs. the name) flipped around. So when I show it in the table, the PersonName is in the ID column and the ID is in the person column. Here is the JSON result.

{"total":1,"page":1,"records":6,"rows":[{"i":5,"cell":[" 5","Five"]},{"i":4,"cell":["Four","    4"]},{"i":1,"cell":["         1","One"]},{"i":6,"cell":["Six","      6"]},{"i":3,"cell":["         3","Three"]},{"i":2,"cell":["Two","    2"]}]}

Anybody have any insight into what I've done wrong that causes this to happen?

Update

So, I have learned that, what is happening, is that my array values are flipping for every other item in the array. For example...if I populate my database with:

[A, B, C]

then for every even-numbered result (or odd, if you're counting from 0), my data is coming back:

[C, B, A]

So, ultimately, my JSON row data is something like:

[A, B, C] [C, B, A] [A, B, C] [C, B, A] ...etc

This is always happening and always consistent. I am going a bit crazy trying to figure out what's going on because it seems like it should be something simple.

Answer 1

I found the solution here: linq to entities orderby strange issue

The issue ultimately stems from the fact that Linq to Entities has trouble handling strings. When I was using the SqlFunctions.StringConvert method, this was incorrectly performing the conversion (although, I must admit that I don't fully understand why the order was then switched around).

In either case, per the above post, the solution for fixing the problem was to do the selection locally so that I could "force" Linq to Entities to work with strings properly. From this, my final code is:

var people = repository.FindAllPeople()
             .OrderBy(sidx + " " + sord)
             .Skip(pageIndex * pageSize)
             .Take(pageSize);

// Due to a problem with Linq to Entities working with strings,
// all string work has to be done locally.
var local = people.AsEnumerable();
var rowData = local.Select(person => new
        {
            id = person.PersonID,
            cell = new List<string> { 
                person.PersonID.ToString(),
                person.PersonName
            }
        }
    ).ToArray();

var jsonData = new
{
    total = totalPages,
    page = page,
    records = totalRecords,
    rows = rowData
};

return Json(jsonData);

Answer 2

Try to use the method described here. If you use fields instead of properties in the repository.FindAllPeople() you should look at the commented part of the code where are used FieldInfo and GetField instead of PropertyInfo and GetProperty.

Answer 3

I have the same problem with my data which are INT type. If elements in my queue (A,B,C) are NVARCHAR type I do not have this problem. So problem is obviously in SqlFunction.StringConvert function.