How to extract text from PDF file in asp.net with C#2.0 using IText library?

using iTextSharp.text.pdf.parser;

using System.Configuration;
using System.Collections;
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 System.IO;
using System.Xml;
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.text.pdf.parser;
using System.Text;

public void ReadPdfFile(string fileName)
{
    StringBuilder text = new StringBuilder();

    PdfReader pdfReader = new PdfReader(fileName);

    for (int page = 1; page <= pdfReader.NumberOfPages; page++)
    {
        //ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
        //string currentText = PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy);

        currentText = Encoding.UTF8.GetString(Encoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.UTF8.GetBytes(currentText)));
        text.Append(currentText);
        pdfReader.Close();
     }

     string s = text.ToString();
}