Find number of pages in a PDF file using C# .Net

This Way:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            string ppath = Server.MapPath("~/Docs/Doc1.pdf");
            PdfReader pdfReader = new PdfReader(ppath);
            int numberOfPages = pdfReader.NumberOfPages;
            Response.Write(numberOfPages);
        }
    }

Download the Latest iTextSharp.dll

Without using iTextSharp.dll

protected void Page_Load(object sender, EventArgs e)
    {
        FileStream fs = new FileStream(Server.MapPath("Docs/Doc1.pdf"), FileMode.Open, FileAccess.Read);
        StreamReader r = new StreamReader(fs);
        string pdfText = r.ReadToEnd();
        Regex rx1 = new Regex(@"/Type\s*/Page[^s]");
        MatchCollection matches = rx1.Matches(pdfText);
        Response.Write("The PDF file has " + matches.Count.ToString() + " page(s).");
    }  

namespace:

using System.IO;
using System.Text.RegularExpressions;

Thank You.