Object reference not set to an instance of an object. RSS

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  coolvaas1

  Participant

  938 Points

  435 Posts

  Object reference not set to an instance of an object.

  May 27, 2010 06:09 PM|LINK

  I have the following code in my form load that loads the reports and assigns it to crystalreportviewer control.

  If Not IsPostBack Then 

  Dim rpt As New ReportDocument
  rpt.Load("C:\Inetpub\wwwroot\Portal\Reports\detailvw.rpt")
  
  
  Dim crLogin As New ApplyCRLogin
  crLogin._dbName = ""
  crLogin._serverName = "prod_fin"
  
  
  crLogin._userID = "finprod"
  crLogin._passWord = "fin!@#"
  
  
  crLogin.ApplyInfo(Session("rpt"))
  crLogin = Nothing
  
  
  CrystalReportPartsViewer1 = rpt

  End If
  

  Following is the ApplyCRLogin Class

  Imports CrystalDecisions.Shared
  Imports CrystalDecisions.CrystalReports.Engine
  Imports CrystalDecisions.Web
  Imports Microsoft.VisualBasic
  
  Public Class ApplyCRLogin
      Public _dbName As String
      Public _serverName As String
      Public _userID As String
      Public _passWord As String
      Public _integratedSecurity As Boolean
      Public _reportType As Integer 'QHR or Virtuo report
  
  
      Public Sub ApplyInfo(ByRef _oRpt As CrystalDecisions.CrystalReports.Engine.ReportDocument)
          Dim oCRDb As CrystalDecisions.CrystalReports.Engine.Database = _oRpt.Database()
          Dim oCRTables As CrystalDecisions.CrystalReports.Engine.Tables = oCRDb.Tables()
          Dim oCRTable As CrystalDecisions.CrystalReports.Engine.Table
          Dim oCRTableLogonInfo As CrystalDecisions.Shared.TableLogOnInfo
          Dim oCRConnectionInfo As New CrystalDecisions.Shared.ConnectionInfo
  
          oCRConnectionInfo.ServerName = _serverName
          oCRConnectionInfo.UserID = _userID
          oCRConnectionInfo.Password = _passWord
          oCRConnectionInfo.IntegratedSecurity = _integratedSecurity
  
          For Each oCRTable In oCRTables
              oCRTableLogonInfo = oCRTable.LogOnInfo()
              oCRTableLogonInfo.ConnectionInfo = oCRConnectionInfo
              oCRTable.ApplyLogOnInfo(oCRTableLogonInfo)
          Next
          oCRTables(0).TestConnectivity()
  
          If Len(Trim(_dbName)) = 0 Then
          Else
              _oRpt.DataSourceConnections(0).SetConnection(_serverName, _dbName, _userID, _passWord)
          End If
      End Sub
  
      Private Sub SetDBLogonForReport(ByVal myConnectionInfo As ConnectionInfo, ByVal myReportDocument As ReportDocument)
          Dim myTables As Tables = myReportDocument.Database.Tables
          For Each myTable As CrystalDecisions.CrystalReports.Engine.Table In myTables
              Dim myTableLogonInfo As TableLogOnInfo = myTable.LogOnInfo
              myTableLogonInfo.ConnectionInfo.AllowCustomConnection = True
              myTableLogonInfo.ConnectionInfo = myConnectionInfo
              myTable.ApplyLogOnInfo(myTableLogonInfo)
          Next
          myReportDocument.DataSourceConnections(0).SetConnection(_serverName, _dbName, _userID, _passWord)
      End Sub
  
      Private Sub SetDBLogonForSubreports(ByVal myConnectionInfo As ConnectionInfo, ByVal myReportDocument As ReportDocument)
          Dim mySections As Sections = myReportDocument.ReportDefinition.Sections
          For Each mySection As Section In mySections
              Dim myReportObjects As ReportObjects = mySection.ReportObjects
              For Each myReportObject As ReportObject In myReportObjects
                  If myReportObject.Kind = ReportObjectKind.SubreportObject Then
                      Dim mySubreportObject As SubreportObject = CType(myReportObject, SubreportObject)
  
                      Dim subReportDocument As ReportDocument = mySubreportObject.OpenSubreport(mySubreportObject.SubreportName)
  
                      SetDBLogonForReport(myConnectionInfo, subReportDocument)
                  End If
              Next
          Next
      End Sub
  End Class
  

  
  Now when I run the site it prompts me for the parameters and when I enter them and click on OK, I get the following error.

  "Object reference not set to an instance of an object."

  But the strange thing is if I comment the "If Not IsPostBack Then" condition, my report works fine. The problem is even when I want to go to the next page in report, the code get executed again and this takes time. Is there any other way to fix this?

  Any help is greatly appreciated.

   

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  jasonjanofsk...

  Participant

  1022 Points

  213 Posts

  Re: Object reference not set to an instance of an object.

  May 28, 2010 03:52 AM|LINK

  Your page is not working -- I am thinking -- due to the nature of the page lifecycle.  If you have your db connection strings all setup in a block of code that is run in your page_load event and only run on the first load of the page (not ispostback).  Your variables get set the first time someone loads the page, but on subsequent postbacks, the variables are not set, hence the object reference.  If you take out the not ispostback, you get the variables set every time but the page then has to run that code every time the user takes a postback action on the page.

  If you can, I would suggest making some alterations to your class, or making a class that loads your settings before calling your class.  Store your data in your web config and use:

  System.ConfigurationManager.AppSettings["MyDBUserName"] to pull the proper data.  If the data is stored per user, use the httpcontext.current.session object for the user and store the correct data on login.

  Check my blog at: http://jasonjano.wordpress.com
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  nareshguree2...

  Star

  11118 Points

  1997 Posts

  Re: Object reference not set to an instance of an object.

  May 28, 2010 04:29 AM|LINK

  when you work in Not page.IspostBack then Crystal Report work fine.

  but after page life cycle, crystal report other event did not fire due to past back.

  when you using this need to put all the code on page load without not postback, And

  with Not IsPostback you bind the crystal report on button click.

  
  

  and try this as well

  protected void Page_UnLoad(object sender, EventArgs e)
      {
          if (mb_objcryRptDoc != null)
          {
              mb_objcryRptDoc.Close();
              mb_objcryRptDoc.Dispose();
          }
      }

  
  

  it will be work fine.

  
  

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  coolvaas1

  Participant

  938 Points

  435 Posts

  Re: Object reference not set to an instance of an object.

  May 28, 2010 01:46 PM|LINK

  Thanks for the reply. I tried it and it doesn't work. 

   Instead of using crystalreportsviewer= reportdocument, I added a crystalreportsource in to the form and in the viewer properties I assign that and loaded the report to crystalreportsource1. Then it works without any issues, but I need to use the reportdocument object.

  Any way that I can assigna reportdocument object to a crystalreportsource? Even this will help me out.