How to: Merge the Pages of Two Reports

• May 22, 2020
• 3 minutes to read

This example demonstrates how to modify report content before it is displayed by handling the ReportDataSourceHelper.BeforeShowPreview event. To add a separate report to the end of another report, refer to the Add a Report to the End/Beginning topic.

Note

Mobile applications do not support the report preview mechanism, so the approach described in this topic cannot be implemented in the Mobile platform.

In this topic, it is assumed that you have an XAF application that uses the Reports V2 Module, and you have created one or more reports (see Reports V2 Module Overview).

To merge two reports right before they are displayed, implement the following helper class, which handles the ReportDataSourceHelper.BeforeShowPreview event. In this example, pages from the SecondReport will be appended to the pages of the FirstReport when the FirstReport is previewed.

C#

using System;
using DevExpress.XtraReports.UI;
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.ReportsV2;
// ...
public class MergeReportHelper {
    ReportDataSourceHelper helper;
    public MergeReportHelper(ModuleList modules) {
        ReportsModuleV2 module = ReportsModuleV2.FindReportsModule(modules);
        if (module != null) {
            module.ReportsDataSourceHelper.BeforeShowPreview +=
                ReportsDataSourceHelper_BeforeShowPreview;
        }
    }
    private void ReportsDataSourceHelper_BeforeShowPreview(
        object sender, BeforeShowPreviewEventArgs e) {
        MergeReportsBeforeShow(e.Report, (ReportDataSourceHelper)sender);
    }
    private void MergeReportsBeforeShow(
        XtraReport report, ReportDataSourceHelper reportsDataSourceHelper) {
        if (report is FirstReport) {
            report.AfterPrint += report_AfterPrint;
            helper = reportsDataSourceHelper;
        }
    }
    void report_AfterPrint(object sender, EventArgs e) {
        FirstReport firstReport = sender as FirstReport;
        SecondReport secondReport = new SecondReport();
        helper.SetupReport(secondReport);
        secondReport.CreateDocument(false);
        firstReport.ModifyDocument(x => x.AddPages(secondReport.Pages));
        firstReport.PrintingSystem.ContinuousPageNumbering = true;
    }
}

VB.NET

Imports System
Imports DevExpress.XtraReports.UI
Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.ReportsV2
' ...
Public Class MergeReportHelper
    Private helper As ReportDataSourceHelper
    Public Sub New(ByVal modules As ModuleList)
        Dim [module] As ReportsModuleV2 = ReportsModuleV2.FindReportsModule(modules)
        If [module] IsNot Nothing Then
            AddHandler [module].ReportsDataSourceHelper.BeforeShowPreview,
                AddressOf ReportsDataSourceHelper_BeforeShowPreview
        End If
    End Sub
    Private Sub ReportsDataSourceHelper_BeforeShowPreview(ByVal sender As Object,
        ByVal e As BeforeShowPreviewEventArgs)
        MergeReportsBeforeShow(e.Report, DirectCast(sender, ReportDataSourceHelper))
    End Sub
    Private Sub MergeReportsBeforeShow(ByVal report As XtraReport,
        ByVal reportsDataSourceHelper As ReportDataSourceHelper)
        If TypeOf report Is FirstReport Then
            AddHandler report.AfterPrint, AddressOf report_AfterPrint
            helper = reportsDataSourceHelper
        End If
    End Sub
    Private Sub report_AfterPrint(ByVal sender As Object, ByVal e As EventArgs)
        Dim firstReport As FirstReport = TryCast(sender, FirstReport)
        Dim secondReport As New SecondReport()
        helper.SetupReport(secondReport)
        secondReport.CreateDocument(False)
        firstReport.ModifyDocument(Sub(x) x.AddPages(secondReport.Pages))
        firstReport.PrintingSystem.ContinuousPageNumbering = True
    End Sub
End Class

The ReportDataSourceHelper.SetupReport method call is required to display a report in XAF. Without it, the data source will not provide data.

Create an instance of the MergeReportHelper class after the application setup is complete. You can do it in the platform-agnostic module by handling the XafApplication.SetupComplete event in the overridden ModuleBase.Setup method.

C#

public override void Setup(XafApplication application) {
    base.Setup(application);
    application.SetupComplete += delegate(object sender, EventArgs e) {
        new MergeReportHelper(((XafApplication)sender).Modules);
    };
}

VB.NET

Public Overrides Sub Setup(ByVal application As XafApplication)
    MyBase.Setup(application)
    AddHandler application.SetupComplete, Sub(sender As Object, e As EventArgs)
        Dim TempMergeReportHelper As MergeReportHelper =
        New MergeReportHelper(CType(sender, XafApplication).Modules)
    End Sub
End Sub