I wrote series of articles about create PDF document in ASP.NET with C# using iTextSharp. In this article I’m going to explain how to set PDF document size. Other articles related to iTextSharp
How to create PDF document using iTextSharp
How to use Images in PDF document using iTextSharp
Image alignment in PDF document using iTextSharp
How to use Tables in PDF document using iTextSharp
How to export GridView records to PDF document using iTextSharp
Here I’m going to explain how to change PDF document page size in using iTextSharp. First we have to download iTextSharp.dll class library and include to our project. You can download iTextSharp.dll class library here
http://sourceforge.net/projects/itextsharp/
Then open your project and include that iTextSharp.dll class library.

Browse the iTextSharp.dll file which is downloaded now and click ok.

In this first article about iTextSharp I just explain how to change PDF document page size.
iTextSharp provides a way to change PDF document page size. We can customize page size by using either Rectangle or PageSize function.
Rectangle method:
Document document = new Document(new Rectangle(200f, 300f));
PageSize method:
Document document = new Document(PageSize.A4, 20f, 20f, 20f, 20f);
You can create your designer page now
Designer source code:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="btnShow" runat="server" Text="Show PDF"
OnClick="btnShow_OnClick"/>
</div>
</form>
</body>
</html>
Here you have to use following namespaces and create one folder for store PDF documents
using iTextSharp.text;
using iTextSharp.text.pdf;
using System.IO;
Code Behind:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using iTextSharp;
using iTextSharp.text;
using iTextSharp.text.pdf;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
//server folder path which is stored your PDF documents
string path = Server.MapPath("PDF-Files");
string filename = path + "/Doc1.pdf";
//Create new PDF document
Document document = new Document(new Rectangle(200f, 300f));
//Document document = new Document(PageSize.A4, 20f, 20f, 20f, 20f);
PdfWriter.GetInstance(document, new FileStream(filename, FileMode.Create));
document.Open();
document.Add(new Paragraph("Welcome to dotnetfox"));
document.Close();
ShowPdf(filename);
}
public void ShowPdf(string filename)
{
//Clears all content output from Buffer Stream
Response.ClearContent();
//Clears all headers from Buffer Stream
Response.ClearHeaders();
//Adds an HTTP header to the output stream
Response.AddHeader("Content-Disposition", "inline;filename=" + filename);
//Gets or Sets the HTTP MIME type of the output stream
Response.ContentType = "application/pdf";
//Writes the content of the specified file directory to an HTTP response output stream as a file block
Response.WriteFile(filename);
//sends all currently buffered output to the client
Response.Flush();
//Clears all content output from Buffer Stream
Response.Clear();
}
}