using System;

using HtmlAgilityPack;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(StripHtmlTags("<p>This is a test string.&nbsp;</p>"));

    }

    public static string StripHtmlTags(string input)

    {

        var doc = new HtmlDocument();

        doc.LoadHtml(input ?? "");

        return doc.DocumentNode.InnerText;

    }

}