DataView dvDetails = new DataView(_dtDetails); // _dtDetails is a datatable
rptSubHistory rptSubHistory = new rptSubHistory(dvDetails);
rptSubHistory.DataSource = dvDetails;
subHistory.Report = rptSubHistory;

public void rptSubHistory_FetchData(object sender, GrapeCity.ActiveReports.SectionReport.FetchEventArgs eArgs)
  {
       _intRecordCount++;
  }

public void Detail_Format(object sender, System.EventArgs eArgs)
  {
      if (_dvDetails.Count > 0)
      {
          txtColumn.Text = _dvDetails.Table.Rows[_intRecordCount]["ColumnName"].ToString();
          txtOrigValue.Text = _dvDetails.Table.Rows[_intRecordCount]["OrigValue"].ToString();
          txtNewValue.Text = _dvDetails.Table.Rows[_intRecordCount]["CurrentValue"].ToString();
      }
  }