Sporadic issue with ReportViewer - "A data source instance has not been supplied for the data source"

Question

User-883621491 posted

Hi. I have an application that has been working fine for at least 2 years. Around January of this year, some of our tech people made a bunch of changes in the virtual infrastructure, physical networking, etc. to the servers hosting our ASP.NET apps. After these changes (of which there were far too many to be able to isolate), I am now having problems with one of my apps

The app uses a ReportViewer control to display a report. It works most of the time, but sporadically, and such that I can't reproduce it, the users will get an error "A data source instance has not been supplied for the data source", and the report will not display. I am trying to figure out how to either 1) find out from Windows error logs or some other method what is causing this to happen, or 2) be able to work around it so that the user can try to re-run the report if it happens. Here is a sample of the code I am using. I have added the Try...Catch block and the display of a "try again" button to let them try the report again. This error-handling change has not been pushed out yet, so I am not sure if this will help, but I hope so, at least so they can try again. The report they complain about not working the most is the one handled by the report type "KeyReturn" in the code.

Please advise if there is a particular Windows error log I can try to look at to see what is causing this problem, or if there is some other way that I don't know about that I can use to prevent this from happening. Thank you.

    Protected Sub PrintReport()
        Dim BadCall As Boolean = False

        Try
            rvReportViewer.LocalReport.DataSources.Clear()
            Select Case lblRepType.Text
                Case "KeyReceipt"
                    rvReportViewer.LocalReport.ReportPath = "Reports\KeyReceipt.rdlc"

                    Dim reportParameters(0) As ReportParameter
                    reportParameters(0) = New ReportParameter("Building", lblBuildingName.Text)
                    rvReportViewer.LocalReport.SetParameters(reportParameters)

                    ObjectDSKeyReceipt.SelectParameters("CustID").DefaultValue = lblCustID.Text
                    ObjectDSKeyReceipt.SelectParameters("Building").DefaultValue = lblBuildingCode.Text
                    ObjectDSKeyReceipt.SelectParameters("incident").DefaultValue = lblRepOptions.Text
                    ObjectDSKeyReceipt.SelectParameters("RepDate").DefaultValue = lblRepOptions2.Text
                    ''
                    ObjectDSKeyReceiptSubKeycode.SelectParameters("CustID").DefaultValue = lblCustID.Text
                    ObjectDSKeyReceiptSubKeycode.SelectParameters("Building").DefaultValue = lblBuildingCode.Text
                    ObjectDSKeyReceiptSubKeycode.SelectParameters("incident").DefaultValue = lblRepOptions.Text
                    ObjectDSKeyReceiptSubKeycode.SelectParameters("RepDate").DefaultValue = lblRepOptions2.Text
                    ''
                    ObjectDSKeyReceiptSubCurrentCharge.SelectParameters("CustID").DefaultValue = lblCustID.Text
                    ObjectDSKeyReceiptSubCurrentCharge.SelectParameters("Building").DefaultValue = lblBuildingCode.Text
                    ObjectDSKeyReceiptSubCurrentCharge.SelectParameters("incident").DefaultValue = lblRepOptions.Text
                    ObjectDSKeyReceiptSubCurrentCharge.SelectParameters("RepDate").DefaultValue = lblRepOptions2.Text

                    rvReportViewer.LocalReport.DataSources.Add(New ReportDataSource("DataSetKeyReceipt", "ObjectDSKeyReceipt"))
                    AddHandler rvReportViewer.LocalReport.SubreportProcessing, AddressOf SetKeyReceiptSubDataSource
                Case "KeyReturn"
                    rvReportViewer.LocalReport.ReportPath = "Reports\KeyReturn.rdlc"

                    Dim reportParameters(0) As ReportParameter
                    reportParameters(0) = New ReportParameter("Building", lblBuildingName.Text & " Key Receipt")
                    rvReportViewer.LocalReport.SetParameters(reportParameters)

                    ObjectDSKeyReturn.SelectParameters("CustID").DefaultValue = lblCustID.Text
                    ObjectDSKeyReturn.SelectParameters("Building").DefaultValue = lblBuildingCode.Text
                    ObjectDSKeyReturn.SelectParameters("incident").DefaultValue = lblRepOptions.Text
                    ObjectDSKeyReturn.SelectParameters("RepDate").DefaultValue = lblRepOptions2.Text
                    ''
                    ObjectDSKeyReturnSubCharges.SelectParameters("CustID").DefaultValue = lblCustID.Text
                    ObjectDSKeyReturnSubCharges.SelectParameters("Building").DefaultValue = lblBuildingCode.Text
                    ObjectDSKeyReturnSubCharges.SelectParameters("incident").DefaultValue = lblRepOptions.Text
                    ObjectDSKeyReturnSubCharges.SelectParameters("RepDate").DefaultValue = lblRepOptions2.Text

                    rvReportViewer.LocalReport.DataSources.Add(New ReportDataSource("DataSetKeyReturn", "ObjectDSKeyReturn"))
                    AddHandler rvReportViewer.LocalReport.SubreportProcessing, AddressOf SetKeyReturnSubDataSource
                Case "LateKeyNotification"
                    rvReportViewer.LocalReport.ReportPath = "Reports\LateKey.rdlc"

                    Dim reportParameters(0) As ReportParameter
                    reportParameters(0) = New ReportParameter("Building", lblBuildingName.Text)
                    rvReportViewer.LocalReport.SetParameters(reportParameters)

                    ObjectDSLateKey.SelectParameters("CustID").DefaultValue = lblCustID.Text
                    ObjectDSLateKey.SelectParameters("Building").DefaultValue = lblBuildingCode.Text
                    ObjectDSLateKey.SelectParameters("incident").DefaultValue = lblRepOptions.Text

                    rvReportViewer.LocalReport.DataSources.Add(New ReportDataSource("DataSetLateKey", "ObjectDSLateKey"))
                Case "KeysOut"
                    rvReportViewer.LocalReport.ReportPath = "Reports\KeysOut.rdlc"

                    Dim reportParameters(0) As ReportParameter
                    reportParameters(0) = New ReportParameter("BuildingName", lblBuildingName.Text)
                    rvReportViewer.LocalReport.SetParameters(reportParameters)

                    ObjectDSKeysOut.SelectParameters("Building").DefaultValue = lblBuildingCode.Text

                    rvReportViewer.LocalReport.DataSources.Add(New ReportDataSource("DataSetKeysOut", "ObjectDSKeysOut"))
                Case Else
                    BadCall = True
            End Select
            If Not BadCall Then
                rvReportViewer.ProcessingMode = ProcessingMode.Local
                rvReportViewer.Visible = True
                rvReportViewer.LocalReport.Refresh()
            Else
                divReports.Visible = False
                divButtons.Visible = True
                lblError.Text = "There was an error calling this page to print a report. Please close the window/tab. Report requested was " & lblRepType.Text
                btnReprintReport.Visible = False
            End If
        Catch ex As Exception
            divReports.Visible = False
            divButtons.Visible = True
            lblError.Text = "There was an error calling this page to print a report. Please close the window/tab, or try the report again. " &
                "Report requested was '" & lblRepType.Text & "'. The error reported was: " & ex.Message
            btnReprintReport.Visible = True
        End Try
    End Sub
	
    Protected Sub SetKeyReceiptSubDataSource(ByVal sender As Object, ByVal e As SubreportProcessingEventArgs)
        e.DataSources.Add(New ReportDataSource("DataSetKeyReceipt_SubReportKeycode", "ObjectDSKeyReceiptSubKeycode"))
        e.DataSources.Add(New ReportDataSource("DataSetKeyReceipt_SubReportCurrentCharge", "ObjectDSKeyReceiptSubCurrentCharge"))
        e.DataSources.Add(New ReportDataSource("DataSetKeyReceipt_SubReportRecoreCharges", "ObjectDSKeyReceiptSubRecoreCharges"))
    End Sub

    Protected Sub SetKeyReturnSubDataSource(ByVal sender As Object, ByVal e As SubreportProcessingEventArgs)
        e.DataSources.Add(New ReportDataSource("DataSetKeyReturn_SubReportCharges", "ObjectDSKeyReturnSubCharges"))
    End Sub

Answer 1

User-2057865890 posted

Hi M-Clark,

A data source instance has not been supplied for the data source

Please ensure that dataset names are same. The error message indicates the dataset name which you have assigned to report viewer and the dataset name which you use in code behind is different.

Best Regards,

Chris

Answer 2

User-883621491 posted

Thanks for your reply. I'm assuming you saw where I mentioned that it is sporadic? The code works fine 99% of the time, there is just something that happens that causes it to give this error sometimes. I cannot reproduce it because it is so random. If I were assigning the wrong dataset name, it would be happening all the time. I need to know what types of things might cause this. Network issues? Sessions timing out? I need to know how I can troubleshoot what is causing it, via Windows Error logs, or something.

The way this thing works is:

1) User clicks a button to complete a process (i.e. returning a key)

2) Button does some work, then calls a page with the reportviewer code to show the receipt

3) Page with reportviewer takes session variables from the calling page and stores them in hidden labels, then builds the query parameters, etc.

4) Report is shown

Steps 3 and 4 are shown in the code in my original post. As I mentioned also, this worked fine for a long time (around 2 years) before all the behind the scenes server and networking changes, at which time this started. Therefore, I don't believe it is the code, per se, but I need to try to track down what situation causes the error to happen.

Answer 3

User-2057865890 posted

Hi M-Clark,

I need to know how I can troubleshoot what is causing it, via Windows Error logs, or something.

If applications runn under IIS. The browser itself often produces a specific error or set of errors that is enough to resolve the issues. Sometimes you’ll need more information, you could analyze IIS log files in an effort to determine the cause when an application that is hosted on IIS is failing or other issues. 

By default, IIS log files are located in the following directories:

IIS 7 and later: %SystemDrive%\inetpub\logs\LogFiles

You could also go to Administrative Tools, and then click Computer Management. Event Viewer is listed under the System Tools node. The benefit of this display is that IIS Manager is in the same window under the Applications and Services node.

reference:

https://msdn.microsoft.com/en-us/magazine/dn519926.aspx

https://msdn.microsoft.com/en-us/library/ms524984(v=vs.90).aspx

Best Regards,

Chris