An error occurred during report processing. -RLDC reporting in ASP.NET MVC

I have this action to generate reports :

  public ActionResult Report(string id)
            LocalReport lr = new LocalReport();
            string path = Path.Combine(Server.MapPath("~/Report"), "Person.rdlc");
            if (System.IO.File.Exists(path))
                lr.ReportPath = path;
                return View("Index");
            List<Person> cm = new List<Person>();

            var viewModel = new PersonIndexData();

            viewModel.People= db.Person
            .Include(k => k.Groups)
            .OrderBy(k => k.Name);

            cm = viewModel.People.ToList();

            ReportDataSource rd = new ReportDataSource("PersonDataSet", cm);
            string reportType = id;
            string mimeType;
            string encoding;
            string fileNameExtension;

            Warning[] warnings;
            string[] streams;
            byte[] renderedBytes;

            renderedBytes = lr.Render(
                out mimeType,
                out encoding,
                out fileNameExtension,
                out streams,
                out warnings);

            return File(renderedBytes, mimeType);

When I call this action like this : (mysite/person/report/pdf), I get this exception :

An error occurred during report processing.
Indicating this line :

        renderedBytes = lr.Render(
            out mimeType,
            out encoding,
            out fileNameExtension,
            out streams,
            out warnings);

Can you tell me why I’m getting this exception in this code? It doesn’t give any error and the exception is not very explanatory. I’m using EF-code first. Thank you.


Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Have you try like this after adding a TableAdapter? It is working perfectly for me.

public FileResult Report(string id)
    PersonTableAdapter ta = new PersonTableAdapter();
    PersonDataSet ds = new PersonDataSet();

    //for avoiding "Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints." error
    ds.EnforceConstraints = false;

    ta.Fill(ds.Person, id); //You might customize your data at this step i.e. applying a filter

    ReportDataSource rds = new ReportDataSource();
    rds.Name = "ReportingDataSet";
    rds.Value = ds.Person;

    ReportViewer rv = new Microsoft.Reporting.WebForms.ReportViewer();
    rv.ProcessingMode = ProcessingMode.Local;
    rv.LocalReport.ReportPath = Server.MapPath("~/Report/Person.rdlc");

    // Add the new report datasource to the report.
    rv.LocalReport.EnableHyperlinks = true;

    byte[] streamBytes = null;
    string mimeType = "";
    string encoding = "";
    string filenameExtension = "";
    string[] streamids = null;
    Warning[] warnings = null;

    streamBytes = rv.LocalReport.Render("PDF", null, out mimeType, out encoding, out filenameExtension, out streamids, out warnings);

    return File(streamBytes, mimeType, "Person" + "_" + id + ".pdf");

Hope this helps…

Method 2

I’m not sure which one will help you, so I list them as following:

  1. Try removing the datasource from the Report menu and then adding it
  2. Check Render function requirements before action, so you may wanna check in and out parameter values.
  3. Try to see some examples around LocalReporter to be more aware how to use this tool.

And Finally, The line which throws exception is not the same as main code, since you place null instead of deviceInfo! regards.

Method 3

My solution for rdlc is based on ReportViewer.

        byte[] bytes = null;
        string attachmentName = string.Empty;

        Warning[] warnings;
        string[] streamids;
        string mimeType;
        string encoding;
        string extension;
        /*GetReportDataSources(logicResult, spec);*/
        var reportPath = GetReportExecutionPath();

        ReportViewer viewer = new ReportViewer();
        /*viewer.LocalReport.SubreportProcessing +=
            new Microsoft.Reporting.WinForms.SubreportProcessingEventHandler(LocalReport_SubreportProcessing);*/
        viewer.LocalReport.ReportPath = reportPath;
        viewer.LocalReport.EnableExternalImages = true;

        viewer.LocalReport.DisplayName = "displayName";
        bytes = viewer.LocalReport.Render("PDF", null, out mimeType, out encoding, out extension,
            out streamids, out warnings);

/*some logic */

        return new StreamResponse(() =>
            var pdfOutput = new MemoryStream(bytes); 
            pdfOutput.Seek(0, SeekOrigin.Begin);
            return pdfOutput;
        }, "application/pdf").WithHeader("Content-Disposition", "attachment; filename=" + attachmentName);

You need also add report path, and datasources (my solution is complicated, and I use for that LocalReport_SubreportProcessing).

P.S. Using rdlc with ASP.MVC have 1 issue. You need set on ISS App Pool “Identity = LocalSystem”, that is ok in Intranet, but not ok in Internet.

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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