HtmlEncode but leave tags intact | C# Online Compiler

HtmlEncode but leave tags intact by SlackrHackr

using System;
using System.Web;
using System.Xml;
using HtmlAgilityPack;
					
public class Program
{
	public static void Main()
	{
		var html =
        @"<body>
            <h1>This is <b>bold</b> heading</h1>
            <p>This is <u>underlined & <b>bold</b></u> paragraph</p>
        </body>";
		
		Console.Write(HtmlEncode(html));	
	}
	
	public static string HtmlEncode(string html)
    {
        if (html == null) return null;

        var doc = new HtmlAgilityPack.HtmlDocument();
        doc.LoadHtml(html);
		doc.OptionWriteEmptyNodes = true;

        EncodeNode(doc.DocumentNode);

        return doc.DocumentNode.InnerHtml;
    }

    private static void EncodeNode(HtmlNode node)
    {
        if (node.HasChildNodes)
        {
            foreach (var childNode in node.ChildNodes)
            {
                if (childNode.NodeType == HtmlNodeType.Text)
                {
                    childNode.InnerHtml = HttpUtility.HtmlEncode(childNode.InnerHtml);
                }
                else
                {
                    EncodeNode(childNode);
                }
            }
        }
        else if (node.NodeType == HtmlNodeType.Text)
        {
            node.InnerHtml = HttpUtility.HtmlEncode(node.InnerHtml);
        }
    }
}

​x
 
using System;
using System.Web;
using System.Xml;
using HtmlAgilityPack;
                    
public class Program
{
    public static void Main()
    {
        var html =
        @"<body>
            <h1>This is <b>bold</b> heading</h1>
            <p>This is <u>underlined & <b>bold</b></u> paragraph</p>
        </body>";
        
        Console.Write(HtmlEncode(html));    
    }
    
    public static string HtmlEncode(string html)
    {
        if (html == null) return null;
​
        var doc = new HtmlAgilityPack.HtmlDocument();
        doc.LoadHtml(html);
        doc.OptionWriteEmptyNodes = true;
​
        EncodeNode(doc.DocumentNode);
​
        return doc.DocumentNode.InnerHtml;
    }
​
    private static void EncodeNode(HtmlNode node)
    {
        if (node.HasChildNodes)
        {
            foreach (var childNode in node.ChildNodes)
            {
                if (childNode.NodeType == HtmlNodeType.Text)
                {
                    childNode.InnerHtml = HttpUtility.HtmlEncode(childNode.InnerHtml);
                }
                else
                {
                    EncodeNode(childNode);
                }
            }
        }
        else if (node.NodeType == HtmlNodeType.Text)
        {
            node.InnerHtml = HttpUtility.HtmlEncode(node.InnerHtml);
        }
    }
}

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