Crystal report is not displayed in the web page

Imports CrystalDecisions.CrystalReports.Engine
Imports CrystalDecisions.Shared
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration


Public Class WebForm3
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim rptDoc As ReportDocument = New ReportDocument
        Dim ds As DataSet1 = New DataSet1
        Dim dt As DataTable = New DataTable
        ' Just set the name of data table
        dt.TableName = "Crystal Report Example"
        dt = getAllOrders
        'This function is located below this function
        ds.Tables(0).Merge(dt)
        ' Your .rpt file path will be below
        rptDoc.Load(Server.MapPath("CrystalReport4.rpt"))
        'set dataset to the report viewer.
        rptDoc.SetDataSource(ds)
        rptDoc.ExportToDisk(ExportFormatType.Excel, Server.MapPath("myExcelFile.xls"))
        CrystalReportViewer1.ReportSource = rptDoc


    End Sub

    Public Function getAllOrders() As DataTable
        'Connection string replace 'databaseservername' with your db server name
        Dim sqlCon As String = ("myConnectionString")
        Dim Con As SqlConnection = New SqlConnection(sqlCon)
        Dim cmd As SqlCommand = New SqlCommand
        Dim ds As DataSet = Nothing
        Dim adapter As SqlDataAdapter
        Try
            Con.Open()
            'Stored procedure calling. It is already in sample db.
            cmd.CommandText = "Select Top 23 X,Y From myTable"
            cmd.CommandType = CommandType.Text
            cmd.Connection = Con
            ds = New DataSet
            adapter = New SqlDataAdapter(cmd)
            adapter.Fill(ds, "Users")
        Catch ex As Exception
            Throw New Exception(ex.Message)
        Finally
            cmd.Dispose()
            If (Con.State <> ConnectionState.Closed) Then
                Con.Close()
            End If
        End Try
        Return ds.Tables(0)
    End Function

End Class