Multiple instances of Crystal Reports Viewer possible in WPF?

Question

Hi, I've dragged and dropped three Crystal Reports Viewer controls on my WPF application. The goal is to be able to select up to 3 reports from a listbox and click run to generate the reports simultaneously. When I select just one report, it works fine. However when I select multiple reports it throws errors (object not found, etc). It seems there is a problem with multiple threads. Is it possible to have multiple instances of the Crystal Report Viewer display reports simultaneously? I am using version 13.0.9.1312 from the link below along with VS2013 C# WPF.
SAP Crystal Reports, developer version for Microsoft Visual Studio: Updates & Runtime Downloads
Thanks,
Syed

Answer 1

I was able to quickly cobble together a two viewer app that looks like this:
The code is like this:
Public Sub New()
        ' This call is required by the designer.
        InitializeComponent()
        ' Add any initialization after the InitializeComponent() call.
        Dim crReportDocument As New CrystalDecisions.CrystalReports.Engine.ReportDocument
        crReportDocument.Load("C:\tests\formulas.rpt")
        CrystalReportsViewer1.ViewerCore.ReportSource = crReportDocument
        Dim crReportDocument2 As New CrystalDecisions.CrystalReports.Engine.ReportDocument
        crReportDocument2.Load("C:\tests\report1.rpt")
        CrystalReportsViewer2.ViewerCore.ReportSource = crReportDocument2
    End Sub
For more details see the document WPF Project Using the Crystal Reports WPF Viewer in 8 Easy Steps
Now a couple of things to keep in mind;
1) The report engine is based on 3 Concurrent Processor License (CPL) model. Meaning you can process at most three reports at the same time. In my test, doing the above code for four reports worked, but the reports are very, very simple - and with saved data. What a "real" world reports will do, I am not sure. I do know that in a web app, the reports are queued up until one report is done and thus a CPL is freed up. You will also need to keep in mind any database connection limits, etc.
2) There is also a Print Job limit. This by default is set to 75. In a nutshell, almost anything done with a report is a Print Job. E.g.; paging, zooming, drilling, searching, etc., etc. In addition subreports are considered to be Print Jobs. Thus a report with one subreport in a detail section that returns a thousand rows of data and therefore running 1000 subreports will error out.
You can read more about Print Job limits here:
Crystal Reports Maximum Report Processing Jobs ... | SCN
- Ludek
Senior Support Engineer AGS Product Support, Global Support Center Canada
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