Can't return a type of IHttpActionResult - WebAPI

Question

Hello all,

 

Firstly, this question is about WebAPI. But as i didnt found WebAPI under Category Dropdown, i posted under .NET General.

 

I'm working on MVC WebAPI, where WebAPI Performs a GET operation. But i'm unable to return type of IHttpActionResult.

Below is my WebAPI GET Action method.

public IHttpActionResult GetDataFromDB()
{
    try
    {
        using (var ctx = new AdventureWorks2012Entities())
        {
            var query = (from d in ctx.Departments
                         join h in ctx.EmployeeDepartmentHistories
 on d.DepartmentID equals h.DepartmentID
                         join s in ctx.Shifts on h.ShiftID equals s.ShiftID
                         join e in ctx.Employees
on h.BusinessEntityID equals e.BusinessEntityID
                         join p in ctx.People
on h.BusinessEntityID equals p.BusinessEntityID
                         select new
                         {
Name = ((p.FirstName == null ? "" : p.FirstName) + " " +
 (p.MiddleName == null ? "" : p.MiddleName) + " " +
(p.LastName == null ? "" : p.LastName)),  MaritalStatus = (e.MaritalStatus == "M" ? "Married" : "Single"),
Gender = (e.Gender == "M" ? "Male" : "FeMale"),
Designation = e.JobTitle,
Department = d.Name,
MajorBranch = d.GroupName
                         }).ToList();
            if (query.Count == 0)
            {
                return NotFound();
            }
            return Ok(query);
        }
    }
    catch (Exception) { return null; }
    finally
    {

    }
}

Above code is working fine when i debug & Line # 29 show data in List format. But on browser it displaying as Error.

 

 

I can view output on Fiddler.

 

Please suggest me to figure out my mistake & achieve this.

 

Thanks in advance.