ASP.NET | Esportare una gridview in PDF

La seguente procedura permette di esportare una gridview in un file pdf utilizzando la libreria ITextSharp

Imports System.IO
Imports iTextSharp.text
Imports iTextSharp.text.pdf
Imports iTextSharp.text.html
Imports iTextSharp.text.html.simpleparser

Public Overloads Overrides Sub VerifyRenderingInServerForm(ByVal control As Control)
End Sub

Protected Sub ExportPDF(ByVal gw As GridView, FileName As String)
     Response.ContentType = "application/pdf"
     Response.AddHeader("content-disposition", "attachment;filename=" & FileName)
     Response.Cache.SetCacheability(HttpCacheability.NoCache)
     Dim sw As New StreamWriter()
     Dim hw As New HtmlTextWriter(sw)
     gw.RenderControl(hw)
     Dim sr As New IO.StringReader(sw.ToString())
     Dim pdfDoc As New Document(PageSize.A4, 10.0F, 10.0F, 10.0F, 0.0F)
     Dim htmlparser As New HTMLWorker(pdfDoc)
     PdfWriter.GetInstance(pdfDoc, Response.OutputStream)
     pdfDoc.Open()
     htmlparser.Parse(sr)
     pdfDoc.Close()
     Response.Write(pdfDoc)
     Response.End()
End Sub