Merging reports into one

diegoo · April 2019

Hi, i need in my mvc .net application to serve, after a user click, a SINGLE pdf file containing n reports merged together.
At the same time these reports must be saved ONE BY ONE in the server file system.
My idea was to the get the PreparedPages from all the single reports and put them in another report, this way:

Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Report totalreport = new Report(); //merge of all reports
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â totalreport.Prepare();

Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â foreach (ReportToCreate r in myreportsqueue)Â Â  //queue of objects containing reports to generate and their parameters
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â {
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Report report = new Report(); //a single report
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â report.SetParameterValue(r.ParName, r.ParValue);
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â report.Prepare(); 
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â PDFExport pdfex = new PDFExport();
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â report.Export(pdfex, fullFilePath); //computed path where to save the report

Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â //add report pages to the total report
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â int pagine = report.PreparedPages.Count;
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â for (int nr=1; nr<=pagine; nr++)
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â {
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â var page = report.PreparedPages.GetPage(nr-1);
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â totalreport.PreparedPages.AddPage(page);
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â }
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â }

Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â //send totalreport to browser
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â MemoryStream stream = new MemoryStream();
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â PDFExport pdf = new PDFExport();
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â totalreport.Export(pdf, stream);

Unfortunately the last line of code gives the error: "Reference to an object not set to an instance...." with this stack trace:

in FastReport.Preview.PreparedPage.StartGetPage(Int32 index)
in FastReport.Export.ExportBase.ExportPageNew(Int32 pageNo)
in FastReport.Export.ExportBase.Export(Report report, Stream stream)

Any hint on how to achieve the result?
THX

Mr.TNT · May 2019

Hi, try something like this:

Report totalReport = new Report();
totalReport.Load("pathToFirstReportTemplate");
totalReport.SetParameterValue("totalReportParamName", "totalReportParamValue");
totalReport.Prepare();

foreach (ReportToCreate r in myReportsQueue)
{
Â Â Â Â totalReport.Load(r.pathToNextReportTemplate);
Â Â Â Â totalReport.SetParameterValue(r.paramName, r.paramValue);
Â Â Â Â totalReport.Prepare(true); // append report
}

MemoryStream memoryStream = new MemoryStream();
PDFExport pdfExport = new PDFExport();
totalReport.Export(pdfExport, memoryStream);

You can use the same instance of the report (totalReport) and only append another reports.

Merging reports into one

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