crReportDocument.Export()

Private Sub Btn_Export_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btn_Export.Click
        Try
            Dim ConnInfo As New ConnectionInfo
            With ConnInfo
                .ServerName = "WASA00150"
                .DatabaseName = "iCalls"
                .UserID = "sa"
                .Password = "courage"
            End With
            Me.CrystalReportViewer1.ParameterFieldInfo.Clear()
            Dim crParameterFieldDefinitions As CrystalDecisions.CrystalReports.Engine.ParameterFieldDefinitions
            Dim crParameterFieldDefinition As CrystalDecisions.CrystalReports.Engine.ParameterFieldDefinition
            If Me.txtSTdate.Text.Trim.Length > 0 Then
                Me.CrystalReportViewer1.ReportSource = Server.MapPath("iCalls_CrystalReport_Department.rpt")
                Dim crDataDef As DataDefinition
  crDataDef = crReportDocument.DataDefinition
                Dim exportFileName As String = "iCalls_CrystalReport_Department.rpt"
                Dim exportPath As String = "D:\SampleCrystalReports\iCalls_Export\test1.pdf"
                Dim crExportOptions As ExportOptions
                Dim crDestOptions As New DiskFileDestinationOptions
                crDestOptions.DiskFileName = exportPath
                crExportOptions = crReportDocument.ExportOptions
                crExportOptions.DestinationOptions = crDestOptions
                crExportOptions.ExportDestinationType = ExportDestinationType.DiskFile
                crExportOptions.ExportFormatType = ExportFormatType.PortableDocFormat
                
  Dim ParamFields As ParameterFields = Me.CrystalReportViewer1.ParameterFieldInfo
                Dim Per As New ParameterField
                Per.ParameterFieldName = "Period"
                Dim ParamCurrentValues As New ParameterValues
                Dim values As New ParameterValues
                Dim Period_Value As New ParameterRangeValue
                Period_Value.StartValue = Me.txtSTdate.Text
                Period_Value.EndValue = Me.txtCLdate.Text
                values.Add(Period_Value)
                crReportDocument.DataDefinition.ParameterFields(0).ApplyCurrentValues(values)
                crReportDocument.Export()
            End If
            For Each cnInfo As TableLogOnInfo In Me.CrystalReportViewer1.LogOnInfo
                cnInfo.ConnectionInfo = ConnInfo
            Next
            Me.CrystalReportViewer1.RefreshReport()
            CrystalReportViewer1.Visible = True            
        Catch ex As Exception
            lblmsg.Text = ex.Message.ToString
        End Try
    End Sub