How to do dynamic orderby in LINQ?

Question

I am trying to get sort the data based on the user input. But the orderby clause is not executed in LINQ. How do i do that ?? Here is my code...

 [HttpGet]
    public JsonResult SortData(String colName , String sortorder)
    {
        using( EmployeeDB db = new EmployeeDB( ) )
        {
            if( sortorder == "desc" )
            {
                var JsonData = new
                {
                    Data = (from emp in db.Employees
                            orderby colName descending
                            select new
                            {
                                EId = emp.EId ,
                                EmployeeName = emp.EmployeeName
                            }).ToList( )
                };
                return Json( JsonData , JsonRequestBehavior.AllowGet );
            }
            else
            {
                var JsonData = new
                {
                    Data = (from emp in db.Employees
                            orderby colName
                            select new
                            {
                                EId = emp.EId ,
                                EmployeeName = emp.EmployeeName
                            }).ToList( )
                };
                return Json( JsonData , JsonRequestBehavior.AllowGet );
            }
        }
    }

Ehsan Sajjad · Answer 1 · 2014-06-04T12:06:11.643

3

You have to do something like this to make it work:

var colName= "EmployeeName";

var Column= typeof(Employee).GetProperty(colName);


Data = (from emp in db.Employees
        select new
        {
         EId = emp.EId ,
         EmployeeName = emp.EmployeeName
        })
        .AsEnumerable()
        .OrderBy(emp => Column.GetValue(emp, null))
        .ToList();

or:

 Data = (from emp in db.Employees
            select new
            {
             EId = emp.EId ,
             EmployeeName = emp.EmployeeName
            })
            .AsEnumerable()
            .OrderBy(i => i.GetType().GetProperty(colName).GetValue(i, null))
            .ToList();

edited Jun 04 '14 at 12:06

answered Jun 04 '14 at 11:32

Ehsan Sajjad

61,834
16
105
160

@Eshan, are you sure order by object will work? I suggested the same, but I'm interested. – mazharenko Jun 04 '14 at 11:38
i have not tested it, but it should work. – Ehsan Sajjad Jun 04 '14 at 11:42
I tried with both of code... It dint work... :( – Uthaiah Jun 04 '14 at 11:45
I am getting this error.. LINQ to Entities does not recognize the method 'System.Object GetValue(System.Object, System.Object[])' method, and this method cannot be translated into a store expression." – Uthaiah Jun 04 '14 at 11:47
updated in question what you did? – Ehsan Sajjad Jun 04 '14 at 11:47
in both cases you get same exception? – Ehsan Sajjad Jun 04 '14 at 11:51
I tried with both of your answer... but i am getting the same error :( – Uthaiah Jun 04 '14 at 11:51
i updated answer try that way – Ehsan Sajjad Jun 04 '14 at 12:06

score 0 · Answer 2 · answered Jun 04 '14 at 11:36

0

from emp in db.Employees
orderby colName
...

Wrong. colName is the same for every employee. It have to be something like emp.EmployeeName.

In your case, I think, you better to try Reflection to get actual values of specific column of specific employee. Smth like that:

order by emp.GetType().GetProperty("colName").GetValue(emp, null)

Ugly. Not sure it will work while value is not casted to it's actual type.

answered Jun 04 '14 at 11:36

mazharenko

565
5
11

No.. Its not getting sorted.. – Uthaiah Jun 04 '14 at 11:49

How to do dynamic orderby in LINQ?

2 Answers2