Object reference not set to an instance of an object - when sorting the table column headers (ASC or DESC)

See more:

C#

ASP.NET

MVC

Hi,

I hope you can help me.

I am trying to sort the jQuery JTable columns, but when I click on the table headers for sorting I get this error "Object reference not set to an instance of an object" in this line of the code and the marked ones is the real culprit.

if (sortDirection == SortDirection.ASC)
                   {
                    // newlist = newlist.OrderBy(item => GetPropertyValue(item, sortExpression)).ToList(); // this one gives error when the page loads in view. So I always comment it out the line
                   }
                   else
                   {
                    newlist = newlist.OrderByDescending(item => GetPropertyValue(item, sortExpression)).ToList(); // this is gives when I sort the columns in View
                   }

Here is my full code for your inspection.

internal enum SortDirection { ASC, DESC }

       public static object GetPropertyValue(object obj, string propertyName)
       {
           return obj == null ? null : obj.GetType().GetProperty(propertyName).GetValue(obj, null);
       }

       [HttpPost]
       public JsonResult TopPlayedInVenueList1(string StartDate = "", string EndDate = "", int jtStartIndex = 0, int jtPageSize = 0, string jtSorting = null)
       {
           try
           {

               if (Request.IsAuthenticated == true)
               {
                   string Path = @"C:\\5Newwithdate-1k.xls";
                   OleDbConnection con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source= '" + Path + "';Extended Properties=" + (char)34 + "Excel 8.0;IMEX=1;" + (char)34 + "");
                   OleDbDataAdapter da = new OleDbDataAdapter("select * from [Sheet1$]", con);
                   con.Close();
                   System.Data.DataTable data = new System.Data.DataTable();
                   da.Fill(data);

                   List<TopPlayed> daa = new List<TopPlayed>();

                   foreach (DataRow p in data.Rows)
                   {
                       TopPlayed top = new TopPlayed()
                       {
                           TrackID = Convert.ToInt32(p.Field<double>("TrackID")),
                           Date = p.Field<DateTime>("DateTimes"),
                           TrackName = p.Field<string>("TrackName"),
                           ArtistName = p.Field<string>("ArtistName"),
                           Times = Convert.ToInt32(p.Field<double>("Times"))
                       };

                       daa.Add(top);
                   }

                   var listOrder = daa.Where(i => i.Date >= Convert.ToDateTime(StartDate) && i.Date <= Convert.ToDateTime(EndDate)).ToList();

                   if (jtStartIndex + 150 > listOrder.ToList().Count)
                   {
                       int val = listOrder.ToList().Count - jtStartIndex;
                       jtPageSize = val;
                   }

                   var newlist = listOrder.OrderByDescending(i => i.Times).ToList().GetRange(jtStartIndex, jtPageSize);

                   if (string.IsNullOrEmpty(jtSorting)) { jtSorting = "Times ASC"; }

                    SortDirection sortDirection = jtSorting.ToLower().Contains("desc") ? SortDirection.DESC : SortDirection.ASC;
                    string sortExpression = sortDirection == SortDirection.DESC ? jtSorting.ToLower().Replace(" desc", "") :
                    jtSorting.ToLower().Contains(" asc") ? jtSorting.ToLower().Replace(" asc", "") : jtSorting;

                   if (sortDirection == SortDirection.ASC)
                   {
                 // newlist = newlist.OrderBy(item => GetPropertyValue(item, sortExpression)).ToList();
                   }
                   else
                   {
                    newlist = newlist.OrderByDescending(item => GetPropertyValue(item, sortExpression)).ToList();
                   }

                   return Json(new { Result = "OK", Records = newlist, TotalRecordCount = listOrder.ToList().Count });
               }
               return Json(new { Result = "ERROR" });
           }
           catch (Exception ex)
           {
               return Json(new { Result = "ERROR", Message = ex.Message });
           }
       }

I am stuck in this sorting bit for almost two months now and I hope that someone can help here. Thanks in advance.