Public Event Drillthrough As DrillthroughEventHandler

Dim instance As ReportViewer
Dim handler As DrillthroughEventHandler

AddHandler instance.Drillthrough, handler

public event DrillthroughEventHandler Drillthrough

public:
event DrillthroughEventHandler^ Drillthrough {
	void add (DrillthroughEventHandler^ value);
	void remove (DrillthroughEventHandler^ value);
}

/** @event */
public void add_Drillthrough (DrillthroughEventHandler value)

/** @event */
public void remove_Drillthrough (DrillthroughEventHandler value)

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

using System;
using System.Data;
using System.Windows.Forms;
using Microsoft.Reporting.WinForms;

public class Demo : Form
{
    private DataTable LoadEmployeesData()
    {
        DataSet dataSet = new DataSet();
        dataSet.ReadXml(@"c:\employees.xml");
        return dataSet.Tables[0];
    }

    private DataTable LoadDepartmentsData()
    {
        DataSet dataSet = new DataSet();
        dataSet.ReadXml(@"c:\departments.xml");
        return dataSet.Tables[0];
    }

    void DemoDrillthroughEventHandler(object sender, 
        DrillthroughEventArgs e)
    {
        LocalReport localReport = (LocalReport)e.Report;
        localReport.DataSources.Add(new ReportDataSource("Employees",
            LoadEmployeesData()));
    }

    public Demo()
    {
        this.Text = "Report Control Demo";
        this.ClientSize = new System.Drawing.Size(950, 600);

        ReportViewer reportViewer = new ReportViewer();

        // Set Processing Mode.
        reportViewer.ProcessingMode = ProcessingMode.Local;

        // Set RDL file.
        reportViewer.LocalReport.ReportPath = @"c:\Departments.rdlc";

        // Supply a DataTable corresponding to each report 
        // data source.
        reportViewer.LocalReport.DataSources.Add(
            new ReportDataSource("Departments", 
            LoadDepartmentsData()));

        // Add a handler for drillthrough.
        reportViewer.Drillthrough += new 
            DrillthroughEventHandler(DemoDrillthroughEventHandler);

        // Add the reportviewer to the form.
        reportViewer.Dock = DockStyle.Fill;
        this.Controls.Add(reportViewer);

        // Process and render the report.
        reportViewer.RefreshReport();
    }

    [STAThread]
    public static int Main(string[] args)
    {
        Application.Run(new Demo());
        return 0;
    }
}

Imports System.Data
Imports Microsoft.Reporting.WinForms

Public Class Form1

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

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

    Public Sub DemoDrillthroughEventHandler(ByVal sender As Object, _
        ByVal e As DrillthroughEventArgs)
        Dim localReport = e.Report
        localReport.DataSources.Add(New ReportDataSource( _
            "Employees", LoadEmployeesData()))
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load

        ReportViewer1.ProcessingMode = ProcessingMode.Local

        Dim localReport = ReportViewer1.LocalReport

        ''Set RDL file. 
        localReport.ReportPath = "c:\My Reports\Departments.rdlc"

        '' Supply a DataTable corresponding to each report 
        '' data source. 
        Dim myReportDataSource = New ReportDataSource( _
            "Departments", LoadDepartmentsData())
        localReport.DataSources.Add(myReportDataSource)

        ''Add a handler for drillthrough. 
        AddHandler ReportViewer1.Drillthrough, _
            AddressOf DemoDrillthroughEventHandler

        '' Process and render the report. 
        Me.ReportViewer1.RefreshReport()

    End Sub
End Class