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LocalReport.SubreportProcessing Event 

Occurs when a subreport is processed.

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

public event SubreportProcessingEventHandler SubreportProcessing
/** @event */
public void add_SubreportProcessing (SubreportProcessingEventHandler value)

/** @event */
public void remove_SubreportProcessing (SubreportProcessingEventHandler value)

JScript supports the use of events, but not the declaration of new ones.

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.

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;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using Microsoft.Reporting.WebForms;

public partial class _Default : System.Web.UI.Page 
    private DataTable orderDetailsData = null;

    private DataTable LoadOrdersData()
        // Load data from XML file
        DataSet dataSet = new DataSet();
        dataSet.ReadXml(@"c:\My Reports\OrderData.xml");
        return dataSet.Tables[0];

    private DataTable LoadOrderDetailsData()
        // Load data from XML file
        DataSet dataSet = new DataSet();
        dataSet.ReadXml(@"c:\My Reports\OrderDetailData.xml");
        return dataSet.Tables[0];

    void DemoSubreportProcessingEventHandler(object sender, SubreportProcessingEventArgs e)
        if (orderDetailsData == null)
            orderDetailsData = LoadOrderDetailsData();
        e.DataSources.Add(new ReportDataSource("DataSet1_OrderDetails", orderDetailsData));
    protected void Page_Load(object sender, EventArgs e)
        if (!IsPostBack)
            // Set RDL file
            ReportViewer1.LocalReport.ReportPath = 
                @"c:\My Reports\Orders.rdlc";

            // Supply a DataTable corresponding to each report dataset
                new ReportDataSource("DataSet1_Orders", 
    // Add a handler for SubreportProcessing
    ReportViewer1.LocalReport.SubreportProcessing += new