Html Agility Pack C#（對於開發者的運行原理）

How to Use HtmlAgilityPack in C#

1. Create a new C# Project.
2. Install the library HtmlAgilityPack.
3. Import the namespace. Create an object.
4. Import data from URL and parse the HTML.
5. Get the required data and dispose of the object.

Introduction to HtmlAgilityPack

HTML Agility Pack is a versatile and powerful HTML parsing library for .NET developers. With the help of its extensive collection of APIs, developers can easily navigate, alter, and extract data from HTML documents. HTML Agility Pack makes working with HTML content programmatically easier for all developers, regardless of experience level.

The capacity of HTML Agility Pack to gently manage HTML that is badly organized or faulty is what makes it unique. It is perfect for online scraping operations where the quality of HTML markup may vary since it uses a forgiving parsing algorithm that can parse even the most badly constructed HTML.

Features of HtmlAgilityPack

Getting Started with HtmlAgilityPack

using HtmlAgilityPack;

// Load HTML content from a file or URL
HtmlWeb web = new HtmlWeb();
var doc = web.Load("https://ironpdf.com/");

// Select specific html nodes and parse html string
HtmlNodeCollection nodes = doc.DocumentNode.SelectNodes("//h1[@class='product-homepage-header product-homepage-header--ironpdf']");

// Iterate through selected nodes and extract content
foreach (HtmlNode node in nodes)
{
    Console.WriteLine(node.InnerText);
}
Console.ReadKey();

using HtmlAgilityPack;

// Load HTML content from a file or URL
HtmlWeb web = new HtmlWeb();
var doc = web.Load("https://ironpdf.com/");

// Select specific html nodes and parse html string
HtmlNodeCollection nodes = doc.DocumentNode.SelectNodes("//h1[@class='product-homepage-header product-homepage-header--ironpdf']");

// Iterate through selected nodes and extract content
foreach (HtmlNode node in nodes)
{
    Console.WriteLine(node.InnerText);
}
Console.ReadKey();

Imports HtmlAgilityPack

' Load HTML content from a file or URL
Private web As New HtmlWeb()
Private doc = web.Load("https://ironpdf.com/")

' Select specific html nodes and parse html string
Private nodes As HtmlNodeCollection = doc.DocumentNode.SelectNodes("//h1[@class='product-homepage-header product-homepage-header--ironpdf']")

' Iterate through selected nodes and extract content
For Each node As HtmlNode In nodes
	Console.WriteLine(node.InnerText)
Next node
Console.ReadKey()

HtmlAgilityPack Operations

Integrating HtmlAgilityPack with IronPdf

安裝 IronPDF

• Launch the Visual Studio project.
• Select "Tools" > "NuGet Package Manager" > "Package Manager Console".
• Input this command into the Package Manager Console:

Install-Package IronPdf

• As an alternative, you can use NuGet Package Manager for Solutions to install IronPDF.

• Search results for the IronPDF package may be browsed, and chosen, and then the "Install" button can be clicked. Visual Studio will take care of the installation and download for you.

  

• The IronPDF package and any dependencies needed for your project will be installed by NuGet.
• IronPDF can be used for your project after installation.

實施邏輯

By integrating the features of both libraries, HTML Agility Pack (HAP) and IronPDF may be implemented in C# to read HTML information and produce PDF documents on the fly. The steps for implementation are listed below, along with a sample code that walks through each one:

1. Load HTML Content using HTML Agility Pack: To load HTML material from a source, such as a file, string, or URL, use the HTML Agility Pack. In this phase, the HTML document is parsed and a manipulable HTML document object is created.
2. Extract Desired Content: To choose and extract particular content from the HTML document, use the HTML Agility Pack in conjunction with XPath or LINQ queries. This could entail choosing elements according to their properties, tags, or hierarchical structure.
3. Convert HTML to PDF using IronPDF: To create a PDF document from the retrieved HTML content, use IronPDF. IronPDF converts HTML material to PDF format with ease while maintaining style and layout.
4. Optional: Customize PDF Output: Use IronPDF to add headers, footers, page numbering, and other dynamic components to customize the PDF output as needed. This step improves the resulting PDF document's appearance and usability.
5. Save or Stream PDF Document: The created PDF document can be streamed straight to the client or browser for download, or it can be saved to a file. IronPDF offers ways to save PDF files to different output streams.

using HtmlAgilityPack;
using IronPdf;
using System;
using System.Text;

class Program
{
    static void Main()
    {
        StringBuilder htmlContent = new StringBuilder();

        // Load HTML content from a file or URL
        HtmlWeb web = new HtmlWeb();
        HtmlDocument doc = web.Load("https://ironpdf.com/");

        // Select specific elements using XPath or LINQ
        HtmlNodeCollection nodes = doc.DocumentNode.SelectNodes("//h1[@class='product-homepage-header product-homepage-header--ironpdf']");

        // Iterate through selected nodes and extract content
        foreach (HtmlNode node in nodes)
        {
            htmlContent.Append(node.OuterHtml);
            Console.WriteLine(node.InnerText);
        }

        // Convert HTML content to PDF using IronPDF
        var Renderer = new HtmlToPdf();
        var PDF = Renderer.RenderHtmlAsPdf(htmlContent.ToString());

        // Save PDF to file
        PDF.SaveAs("output.pdf");
        Console.WriteLine("PDF generated successfully!");
        Console.ReadKey();
    }
}

using HtmlAgilityPack;
using IronPdf;
using System;
using System.Text;

class Program
{
    static void Main()
    {
        StringBuilder htmlContent = new StringBuilder();

        // Load HTML content from a file or URL
        HtmlWeb web = new HtmlWeb();
        HtmlDocument doc = web.Load("https://ironpdf.com/");

        // Select specific elements using XPath or LINQ
        HtmlNodeCollection nodes = doc.DocumentNode.SelectNodes("//h1[@class='product-homepage-header product-homepage-header--ironpdf']");

        // Iterate through selected nodes and extract content
        foreach (HtmlNode node in nodes)
        {
            htmlContent.Append(node.OuterHtml);
            Console.WriteLine(node.InnerText);
        }

        // Convert HTML content to PDF using IronPDF
        var Renderer = new HtmlToPdf();
        var PDF = Renderer.RenderHtmlAsPdf(htmlContent.ToString());

        // Save PDF to file
        PDF.SaveAs("output.pdf");
        Console.WriteLine("PDF generated successfully!");
        Console.ReadKey();
    }
}

Imports HtmlAgilityPack
Imports IronPdf
Imports System
Imports System.Text

Friend Class Program
	Shared Sub Main()
		Dim htmlContent As New StringBuilder()

		' Load HTML content from a file or URL
		Dim web As New HtmlWeb()
		Dim doc As HtmlDocument = web.Load("https://ironpdf.com/")

		' Select specific elements using XPath or LINQ
		Dim nodes As HtmlNodeCollection = doc.DocumentNode.SelectNodes("//h1[@class='product-homepage-header product-homepage-header--ironpdf']")

		' Iterate through selected nodes and extract content
		For Each node As HtmlNode In nodes
			htmlContent.Append(node.OuterHtml)
			Console.WriteLine(node.InnerText)
		Next node

		' Convert HTML content to PDF using IronPDF
		Dim Renderer = New HtmlToPdf()
		Dim PDF = Renderer.RenderHtmlAsPdf(htmlContent.ToString())

		' Save PDF to file
		PDF.SaveAs("output.pdf")
		Console.WriteLine("PDF generated successfully!")
		Console.ReadKey()
	End Sub
End Class

Visit Utilizing IronPDF for Conversion to learn more about the code example.

執行輸出如下所示：

結論

Whether parsing HTML data or creating PDF reports, developers can manage and alter document material with ease thanks to the smooth integration of HTML Agility Pack and IronPDF in C#. Developers can easily and precisely automate operations connected to documents by combining the PDF production features of IronPDF with the parsing capabilities of HTML Agility Pack. The combination of these two libraries provides a strong C# document management solution, regardless of whether you're building dynamic reports or pulling data from web pages.

A perpetual license, a year of software maintenance, and a library upgrade are all included in the $799 Lite bundle. IronPDF provides free licensing with temporal and redistribution limitations. During the trial period, users can evaluate the solution without seeing a watermark. Please go to IronPDF's Licensing Information to learn more about the cost and license.

Learn more about Iron Software libraries.