columns.AddColumn(column =>
                                      {
                                          column.PropertyName("Discount");
                                          column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                                          column.IsVisible(true);
                                          column.Order(5);
                                          column.Width(4);
                                          column.HeaderCell("تخفیف");
                                          column.CalculatedField(
                                          list =>
                                          {
                                              if (list == null)
                                                  return string.Empty;
                                              var amountLesson = list.GetValueOf<sp_Lesson_Peresent_Rpt_Financial_DetailResult>(x => x.AmountLesson);
                                              var discount = list.GetValueOf<sp_Lesson_Peresent_Rpt_Financial_DetailResult>(x => x.Discount);
                                              if (amountLesson == "")
                                              {
                                                  column.Width(0);
                                                  return null;
                                              }
                                              else
                                                  return discount;

                                          });
                                      });
                                      columns.AddColumn(column =>
                                      {
                                          column.PropertyName("DiscountPercents");
                                          column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                                          column.IsVisible(true);
                                          column.Order(6);
                                          column.Width(14);
                                          column.HeaderCell("درصد و نوع تخفیف");
                                          column.CalculatedField(
                                          list =>
                                          {
                                              if (list == null)
                                                  return string.Empty;
                                              var amountLesson = list.GetValueOf<sp_Lesson_Peresent_Rpt_Financial_DetailResult>(x => x.AmountLesson);                                             
                                              var discountPercents = list.GetValueOf<sp_Lesson_Peresent_Rpt_Financial_DetailResult>(x => x.DiscountPercents);
                                              if (amountLesson == "")
                                              {
                                                  column.Width(15);
                                                  var decriptions = list.GetValueOf<sp_Lesson_Peresent_Rpt_Financial_DetailResult>(x => x.DESCRIPTION);
                                                  return decriptions;
                                              }
                                              else
                                                  return discountPercents;

                                          });
                                      });