如何在PDF中使用C#添加頁碼

How to Add Page Numbers in PDF using iTextSharp C#

1. Create a new C# project using any IDE.
2. Create a new PDF object.
3. Add page numbers to the HTML footer.
4. Create a PDF from HTML material.
5. Save a PDF file to your computer.

What is IronPDF

IronPDF is a robust PDF .NET Framework that developers use to produce, view, and edit PDFs with ease. IronPDF is a sophisticated tool that runs on a chromium engine internally. It can convert HTML5, JavaScript, CSS, and picture files to PDF, add custom Headers and Footers, and produce PDFs precisely as they appear in a browser. Many online and net formats, including HTML, ASPX, Razor View, and MVC, are supported by IronPDF.

Install-Package IronPdf

What is iTextSharp

iTextSharp is a flexible library for producing and modifying PDF documents in C#. It offers several features, such as encryption, PDF merging, text and picture extraction, and much more. iTextSharp is an efficient tool for numerous tasks, including adding page numbers to PDFs.

Install-Package iTextSharp

Adding Page Numbers using IronPDF

Adding page numbers to PDF files is made simple through IronPDF's comprehensive library. To illustrate, see the below code.

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        // Create a new HtmlToPdf renderer instance
        var renderer = new HtmlToPdf();

        // Define the HTML content with a header
        string header = "<h1>Hello IronPDF!</h1>";

        // Render the HTML as a PDF document
        PdfDocument pdf = renderer.RenderHtmlAsPdf(header);

        // Define the HTML footer with page numbers
        HtmlHeaderFooter htmlFooter = new HtmlHeaderFooter()
        {
            HtmlFragment = "<center><i>{page} of {total-pages}</i></center>"
        };

        // Add footer to the PDF
        pdf.AddHtmlFooters(htmlFooter);

        // Save the PDF document to a file
        pdf.SaveAs("output.pdf");
    }
}

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        // Create a new HtmlToPdf renderer instance
        var renderer = new HtmlToPdf();

        // Define the HTML content with a header
        string header = "<h1>Hello IronPDF!</h1>";

        // Render the HTML as a PDF document
        PdfDocument pdf = renderer.RenderHtmlAsPdf(header);

        // Define the HTML footer with page numbers
        HtmlHeaderFooter htmlFooter = new HtmlHeaderFooter()
        {
            HtmlFragment = "<center><i>{page} of {total-pages}</i></center>"
        };

        // Add footer to the PDF
        pdf.AddHtmlFooters(htmlFooter);

        // Save the PDF document to a file
        pdf.SaveAs("output.pdf");
    }
}

Imports IronPdf

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		' Create a new HtmlToPdf renderer instance
		Dim renderer = New HtmlToPdf()

		' Define the HTML content with a header
		Dim header As String = "<h1>Hello IronPDF!</h1>"

		' Render the HTML as a PDF document
		Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf(header)

		' Define the HTML footer with page numbers
		Dim htmlFooter As New HtmlHeaderFooter() With {.HtmlFragment = "<center><i>{page} of {total-pages}</i></center>"}

		' Add footer to the PDF
		pdf.AddHtmlFooters(htmlFooter)

		' Save the PDF document to a file
		pdf.SaveAs("output.pdf")
	End Sub
End Class

First, we define the HTML text that has to be turned into a PDF. This HTML content may consist of a single HTML paragraph or an entire HTML page. Next, we make an instance of the HtmlToPdf class, which offers the HTML-to-PDF conversion function RenderHtmlAsPdf.

The HTML content is passed as an argument to the RenderHtmlAsPdf function. We specify the HTML material that has to be turned into a PDF. Page numbers are represented as placeholders, or the {page} of {total-pages} in the footer portion of this HTML text.

The created PDF document is returned by this method as a PdfDocument object. Using the SaveAs method, we save the PDF document to a file with the name "output.pdf". Alternatively, we can use the OpenInDefaultPDFViewer function to open the created PDF document with the system's default PDF reader. We can also use the above method to add page numbers to an existing PDF file.

To learn more about the IronPDF code, refer here.

Adding Page Numbers using iTextSharp

First, let's use iTextSharp to generate a new PDF document. Here's a basic illustration of how to make a new PDF document with a page number:

using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            // Create a new PDF document
            Document doc = new Document();
            PdfWriter writer = PdfWriter.GetInstance(doc, new FileStream("output.pdf", FileMode.Create));

            // Open the document to add content
            doc.Open();
            doc.Add(new Paragraph("Hello, world!"));

            // Attach page number event to PDF writer
            writer.PageEvent = new PageNumberEventHandler();

            // Close the document
            doc.Close();
        }
    }

    public class PageNumberEventHandler : PdfPageEventHelper
    {
        public override void OnOpenDocument(PdfWriter writer, Document document)
        {
            base.OnOpenDocument(writer, document);
        }

        public override void OnEndPage(PdfWriter writer, Document document)
        {
            base.OnEndPage(writer, document);

            // Create a table to hold the page number
            PdfPTable table = new PdfPTable(1);
            table.TotalWidth = 300f;
            table.HorizontalAlignment = Element.ALIGN_CENTER;

            PdfPCell cell = new PdfPCell(new Phrase($"Page {writer.PageNumber}"));
            cell.Border = 0;
            table.AddCell(cell);

            // Write the table at the bottom of the page
            table.WriteSelectedRows(0, -1, 150f, document.Bottom, writer.DirectContent);
        }

        public override void OnCloseDocument(PdfWriter writer, Document document)
        {
            base.OnCloseDocument(writer, document);
        }
    }
}

using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            // Create a new PDF document
            Document doc = new Document();
            PdfWriter writer = PdfWriter.GetInstance(doc, new FileStream("output.pdf", FileMode.Create));

            // Open the document to add content
            doc.Open();
            doc.Add(new Paragraph("Hello, world!"));

            // Attach page number event to PDF writer
            writer.PageEvent = new PageNumberEventHandler();

            // Close the document
            doc.Close();
        }
    }

    public class PageNumberEventHandler : PdfPageEventHelper
    {
        public override void OnOpenDocument(PdfWriter writer, Document document)
        {
            base.OnOpenDocument(writer, document);
        }

        public override void OnEndPage(PdfWriter writer, Document document)
        {
            base.OnEndPage(writer, document);

            // Create a table to hold the page number
            PdfPTable table = new PdfPTable(1);
            table.TotalWidth = 300f;
            table.HorizontalAlignment = Element.ALIGN_CENTER;

            PdfPCell cell = new PdfPCell(new Phrase($"Page {writer.PageNumber}"));
            cell.Border = 0;
            table.AddCell(cell);

            // Write the table at the bottom of the page
            table.WriteSelectedRows(0, -1, 150f, document.Bottom, writer.DirectContent);
        }

        public override void OnCloseDocument(PdfWriter writer, Document document)
        {
            base.OnCloseDocument(writer, document);
        }
    }
}

Imports System.IO
Imports iTextSharp.text
Imports iTextSharp.text.pdf

Namespace ConsoleApp1
	Friend Class Program
		Shared Sub Main(ByVal args() As String)
			' Create a new PDF document
			Dim doc As New Document()
			Dim writer As PdfWriter = PdfWriter.GetInstance(doc, New FileStream("output.pdf", FileMode.Create))

			' Open the document to add content
			doc.Open()
			doc.Add(New Paragraph("Hello, world!"))

			' Attach page number event to PDF writer
			writer.PageEvent = New PageNumberEventHandler()

			' Close the document
			doc.Close()
		End Sub
	End Class

	Public Class PageNumberEventHandler
		Inherits PdfPageEventHelper

		Public Overrides Sub OnOpenDocument(ByVal writer As PdfWriter, ByVal document As Document)
			MyBase.OnOpenDocument(writer, document)
		End Sub

		Public Overrides Sub OnEndPage(ByVal writer As PdfWriter, ByVal document As Document)
			MyBase.OnEndPage(writer, document)

			' Create a table to hold the page number
			Dim table As New PdfPTable(1)
			table.TotalWidth = 300F
			table.HorizontalAlignment = Element.ALIGN_CENTER

			Dim cell As New PdfPCell(New Phrase($"Page {writer.PageNumber}"))
			cell.Border = 0
			table.AddCell(cell)

			' Write the table at the bottom of the page
			table.WriteSelectedRows(0, -1, 150F, document.Bottom, writer.DirectContent)
		End Sub

		Public Overrides Sub OnCloseDocument(ByVal writer As PdfWriter, ByVal document As Document)
			MyBase.OnCloseDocument(writer, document)
		End Sub
	End Class
End Namespace

First, we create a new object for Document and PdfWriter, which allows us to create an empty PDF file. You may include text, photos, tables, and other types of material in your PDF document. Let's use a Paragraph to add some sample text for demonstration purposes. The important step is now to add page numbers to the PDF document. We'll use iTextSharp's page events for this. We start by defining a class that inherits from the PdfPageEventHelper class to be able to override methods that are called when specific events happen during the PDF-generating process.

The OnEndPage function is overridden in this class to add a table that has a single cell containing the current page number. Lastly, before we close the document, we need to connect an instance of our PageNumberEventHandler class to the PdfWriter object. With this configuration, the PageNumberEventHandler class's OnEndPage function will be called each time a new page is added to the PDF document, adding the page number at the bottom of each page. We can also use an existing PDF document to add page numbers.

Conclusion

In summary, IronPDF's specialization, usability, and seamless integration with .NET environments position it as the best option for scenarios requiring HTML to PDF conversion and related functionalities, even though iTextSharp is still a strong competitor in the landscape of C# PDF manipulation libraries. With IronPDF, you can create invoices, reports, and dynamically produced documents from HTML content with the ease, effectiveness, and adaptability required to succeed in the modern development environment.

A permanent license, upgrade options, and a year of software maintenance are all included in IronPDF's Lite edition. The watermarked trial period allows users to assess the product in practical settings. Visit the license page for more details. Go to this website to learn more about Iron Software.