LocalReport.SubreportProcessing Event


Occurs when a subreport is processed.

Namespace:   Microsoft.Reporting.WebForms
Assembly:  Microsoft.ReportViewer.WebForms (in Microsoft.ReportViewer.WebForms.dll)

Public Event SubreportProcessing As SubreportProcessingEventHandler

The SubreportProcessing event is triggered for every instance of the subreport in the main report, and not just for each subreport definition. If a report contains multiple subreports instances from the same report definition, this event is triggered for each instance.

You must supply data for any data sources used in subreports. To do this, you must supply an event handler for the SubreportProcessing event.

You can examine values of parameters passed to the subreport by examining the Parameters property and supplying data corresponding to those parameter values.

If the main report has several subreports, you can examine the ReportPath property of the SubreportProcessingEventArgs class to determine which subreport is being processed and supply data for that subreport.

Please see SubreportProcessingEventArgs for a description of the arguments passed to this event handler.

Legacy Code Example

The following code example implements a master/detail report using subreports. The code loads a sample report that contains a subreport and sets up an event handler to handle the SubreportProcessing event. The arguments passed to the SubreportProcessing event handler include an object encapsulating the subreport. The event handler adds a data source instance to this subreport before it is rendered in the ReportViewer control.

using System;
Imports System.Data
Imports Microsoft.Reporting.WebForms

Partial Class _Default
    Inherits System.Web.UI.Page

    Dim orderDetailsData As DataTable = Nothing

    Private Function LoadOrdersData() As DataTable
        Dim dataSet As New DataSet()
        dataSet.ReadXml("c:\My Reports\OrderData.xml")
        LoadOrdersData = dataSet.Tables(0)
    End Function

    Private Function LoadOrderDetailsData()
        Dim dataSet As New DataSet()
        dataSet.ReadXml("c:\My Reports\OrderDetailData.xml")
        LoadOrderDetailsData = dataSet.Tables(0)
    End Function

    Public Sub DemoSubreportProcessingEventHandler(ByVal sender As Object, ByVal e As SubreportProcessingEventArgs)
        If (orderDetailsData Is Nothing) Then
            orderDetailsData = LoadOrderDetailsData()
        End If
        e.DataSources.Add(New ReportDataSource("DataSet1_OrderDetails", orderDetailsData))

    End Sub

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        If (Not IsPostBack) Then

            ' Set RDL file.
            ReportViewer1.LocalReport.ReportPath = "c:\My Reports\Orders.rdlc"

            ' Supply a DataTable corresponding to each report data source.
            Dim myReportDataSource = New ReportDataSource("DataSet1_Orders", LoadOrdersData())
        End If

        'Add a handler for drillthrough.
        AddHandler ReportViewer1.LocalReport.SubreportProcessing, AddressOf DemoSubreportProcessingEventHandler

    End Sub

End Class
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