[c#] Reading PDF documents in .Net

public string ReadPdfFile(object Filename, DataTable ReadLibray)
{
    PdfReader reader2 = new PdfReader((string)Filename);
    string strText = string.Empty;

    for (int page = 1; page <= reader2.NumberOfPages; page++)
    {
    ITextExtractionStrategy its = new iTextSharp.text.pdf.parser.SimpleTextExtractionStrategy();
    PdfReader reader = new PdfReader((string)Filename);
    String s = PdfTextExtractor.GetTextFromPage(reader, page, its);

    s = Encoding.UTF8.GetString(ASCIIEncoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(s)));
    strText = strText + s;
    reader.Close();
    }
    return strText;
}