not able to get json data from code behind

var source = {
             datatype: "json",
             datafields: [{ name: 'ID' }, { name: 'Name' },
             { name: 'Email' }, { name: 'Address' }, { name: 'Contact' }],
             url: "WebForm2.aspx/Grid"
         };

public static string DataSetToJSON(DataSet ds)
      {

          Dictionary<string,> dict = new Dictionary<string,>();
          foreach (DataTable dt in ds.Tables)
          {
              object[] arr = new object[dt.Rows.Count + 1];

              for (int i = 0; i <= dt.Rows.Count - 1; i++)
              {
                  arr[i] = dt.Rows[i].ItemArray;
              }

              dict.Add(dt.TableName, arr);
          }

          JavaScriptSerializer json = new JavaScriptSerializer();
          return json.Serialize(dict);
      }
    [WebMethod(EnableSession = false)]
      public static string Grid()
      {
          DataTable dtFormsData = new DataTable();
          DataSet dtFormsDataset = new DataSet();
          dtFormsDataset = new DataSet();
          dtFormsData = new DataTable();
          dtFormsData.Columns.Add("ID");
          dtFormsData.Columns.Add("Name");
          dtFormsData.Columns.Add("Email");
          dtFormsData.Columns.Add("Address");
          dtFormsData.Columns.Add("Contact");
          dtFormsData.Rows.Add(1,"Usha", "Usha@Kp.com", "Chennai", "Kp@guntakal");
          dtFormsData.Rows.Add(2,"Chaitu", "ChaituKp@gmail.com", "Chennai", "ChaituKurava@gmail.com");
          dtFormsData.Rows.Add(3,"UshaSanjee", "Ushasanjee@gmail.com", "Hyderabad", "Hyderabad");
          dtFormsData.Rows.Add(4,"ChaituKP", "chaitu@gmail.com", "Chennai", "Cheenai");
          dtFormsDataset.Tables.Add(dtFormsData);
          string result = DataSetToJSON(dtFormsDataset);
      string[] lines = { dtFormsData.Columns[0].ColumnName, dtFormsData.Columns[1].ColumnName, dtFormsData.Columns[2].ColumnName, dtFormsData.Columns[3].ColumnName, dtFormsData.Columns[4].ColumnName };
      System.IO.File.WriteAllLines(@"C:\Users\ADMIN\My Documents\Visual Studio 2012\Projects\JqxGrid\JqxGrid\WriteLines.txt", lines);
         return result;
      }