title: DataSet does not support System.Nullable<>
body: <p>i have an app which has btn to preview report made in crystal report. I added Dataset as datasource of the report and dragged datatable from the toolbox and added the fields I need as columns. I got the instruction from this link <strong>http://aspalliance.com/2049_Use_LINQ_to_Retrieve_Data_for_Your_Crystal_Reports.2</strong>. This is my 2nd report the first one works and did not encounter any prob at all that is why i am confused, not to mention it also has nullable column. the error says: <strong>DataSet does not support System.Nullable&lt;>.</strong></p>
  
  <pre><code>  private void ShowReportView()
      {
  
          string reportFile = "JudgeInfoFMReport.rpt";
          ObservableCollection&lt;tblJudgeFileMaint&gt; judgeFileMaintList;
  
          judgeFileMaintList = GenerateReport();
  
          if (judgeFileMaintList.Count &gt; 0)
          {
              CrystalReportViewerUC crview2 = new CrystalReportViewerUC();
              crview2.SetReportPathFile(reportFile, judgeFileMaintList);
              crview2.ShowDialog();
          }
          else
          {
              System.Windows.MessageBox.Show("No record found.", module, MessageBoxButton.OK, MessageBoxImage.Information);
          }
      }
  
  private ObservableCollection&lt;tblJudgeFileMaint&gt; GenerateReport()
      {
          var result = FileMaintenanceBusiness.Instance.GetAllJudgeInfoList();
          return new ObservableCollection&lt;tblJudgeFileMaint&gt;(result);
      }
  </code></pre>
  
  <p>The error is in the part where I set datasource report.SetDataSource</p>
  
  <pre><code> public bool SetReportPathFile(string reportPathFile, IEnumerable enumerable)
      {
  
              string reportFolder = @"\CrystalReportViewer\Reports\";
              string filename = System.Windows.Forms.Application.StartupPath + reportFolder + reportPathFile;  // "\\Reports\\CrystalReports\\DateWiseEmployeeInfoReport.rpt";
              ReportPathFile = filename;
              report.Load(ReportPathFile);
              report.SetDataSource(enumerable);
              report.SetDatabaseLogon("sa", "admin007");
              bRet = true;
         }
  
          _IsLoaded = bRet;
  
          return bRet;
      }
  </code></pre>
  
  <p>I read some answers and says I should set the null value to DBNUll which I did in the properties window of each column if it is nullable. Can anyone help me please? thanks</p>