DataTable getting null in business layer RSS

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  sumajumd

  Member

  39 Points

  38 Posts

  DataTable getting null in business layer

  Aug 06, 2010 11:59 AM|LINK

   Hi Friends,

  I'm preety new to .NET technology and I'm facing a problem with datatable. The scenario is stated below.

  My application has a three tier architectute

  • UI
  • Business
  • DataAccess

  Here, I'm calling a SP from Data Access layer which will populate a DataTable and return the DataTable back to Business. My source code is like below.

  public System.Data.DataTable Filldata(string strConnString)
          {
              loginDataAccess loginDa = new loginDataAccess();
              SqlConnection Conn= loginDa.createConnection(strConnString);
  
  
              SqlCommand Cmd = new SqlCommand("proc_getAuditReason", Conn);
              Cmd.CommandType = System.Data.CommandType.StoredProcedure;
  
  
              System.Data.DataTable DT = new System.Data.DataTable();
              SqlDataAdapter Sda = new SqlDataAdapter();
  
  
              try
              {
                  Conn.Open();
  
  
                  Sda.SelectCommand = Cmd;
                  Sda.Fill(DT);
  
  
                  if (DT.Rows.Count > 0)
                  {
                      return DT;
                  }
                  else
                  {
                      return null;
                  }
              }
              catch (Exception ex)
              {
                  throw ex;
              }
  
  
              finally
              {
                  Cmd = null;
  
  
                  if (Conn != null)
                  {
                      Conn.Close();
                      Conn.Dispose();
                  }
                  if (Sda != null)
                  {
                      Sda = null;
                      Sda.Dispose();
                  }
                  
  
              }
          }

  Here, when I set debugpoint I can see the DataTable is getting populated by the data so my

  sp idreturning the data. there is no issue with the sp and dataaccess layer method. The problem lies below on my business layer. The source code is like below.

  public System.Data.DataTable Filldata(string strConnString)
          {
              
              
              qualityDataAccess fillauditReasonDa = new qualityDataAccess();
              DataTable getauditReasonDt =new DataTable();
  
              try
              {
                  // The below line is throwing a null reference exception basically here I'm
                 // I'm calling the dataaccess layer method which is returning 
                // the DataTable.
                  getauditReasonDt = fillauditReasonDa.FillAuditReason(strConnString);
  
                  if (getauditReasonDt.Rows.Count > 0)
                  {
                      return getauditReasonDt;
                  }
                  else
                  {
                      return null;
                  }
              }
              
  
              
              catch (Exception ex)
              {
                  throw ex;
              }
              
              finally
              {
                  fillauditReasonDa = null;
                  if (getauditReasonDt != null)
                  {
                      getauditReasonDt = null;
                      getauditReasonDt.Dispose();
  
                  }
              }
              
          }

  
  Please help me as it need to be solved ASAP. Please let me know if you need any further information.

    
  

   

   

• • Reply
  

  macpak

  Member

  408 Points

  132 Posts

  Re: DataTable getting null in business layer

  Aug 06, 2010 06:25 PM|LINK

  Hmm, you say you can call DAL method and everything is ok. And then there's a NullReferenceException. First of all, maybe it's just a typo but the DAL method at the top is called Filldata and in BL you call FillAuditReason. So it's the same method (just the name is different) or it's a different method ? Next thing, if You get NullReferenceException, simply try to debug the code and find what line is throwing the exception. 

• • Reply
  

  sumajumd

  Member

  39 Points

  38 Posts

  Re: DataTable getting null in business layer

  Aug 09, 2010 01:38 PM|LINK

  Hi,

  This issue is resolved. I've used DataTable.Load(SqlCommand.ExecuteReader()) to resolve this issue. I think previously disposing of the datatable in finally was causing the issue. Thanks a ton for your reply.

   

    

  • Marked as answer by Wencui Qian - MSFT on Aug 11, 2010 05:46 AM