C#解析单层html的中的文本,然后拼接起来

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 
 namespace ResolveHtmlText
 {
     class Program
     {
         static void Main(string[] args)
         {
             string text = @"&nbsp;<span style='color:#1F497D'><span>y<span></span>&nbsp; &nbsp;<span style='color:#1F497D;'>1</span>&nbsp;<span style='color:#1F497D;background-color:#123456'>2</span><span style='color:#1F497D;background-color:#123456;text-align:center'>3</span>  <span style='color:#1F497D;background-color:#123456;text-align:center;'>4</span> <span style='color:#1F497D;background-color:#123456;text-align:center;tt-l: 134;'>5</span>ggjf<a>123456</a>";
             Console.WriteLine("原字符串:" + text);
             text = text.Replace("\"", "'");
             text = text.Replace("&quot;", "'");
             text = text.Replace("&nbsp;", "");
             text = text.Replace("&lt;", "<");//将<的转义码&lt;都替换成<
             text = text.Replace("&gt;", ">");//将>的转义码&gt;都替换成>
 
             //string matchStr = @"<\s*[a-zA-Z0-9]+\s*>[^<^>]*<\s*/\s*[a-zA-Z0-9]+\s*>";
             string matchStr = @"<\s*[a-zA-Z0-9]+\s*[a-zA-Z]+\s*=\s*'\s*[a-zA-Z]"
                             + @"+\s*:\s*[^<^>];?'\s*>[^<^>]"
                             + @"*<\s*/\s*[a-zA-Z0-9]+\s*>|<\s*[a-zA-Z0-9]"
                             + @"+\s*(\s*[a-zA-Z-]+\s*=\s*'(\s*[a-zA-Z-]+\s*:"
                             + @"\s*[^:^;^<^>]+\s*;\s*)*(\s*[a-zA-Z-]+\s*:\s*"
                             + @"[^:^;^<^>]+\s*)\s*;?\s*'\s*)*"
                             + @"\s*>[^<^>]*<\s*/\s*[a-zA-Z0-9]+\s*>";
 
             Regex htmlReg = new Regex(matchStr);
             string result = null;
             MatchCollection htmlMatchCollection = htmlReg.Matches(text);
             StringBuilder sb = new StringBuilder();
             
             foreach (Match m in htmlMatchCollection) 
             {
                 if (m != null && m.Groups != null && m.Groups.Count > )
                 {
                     string temp = m.Groups[].Value;
                     Console.WriteLine("临时值:" + temp);
                     //Regex textReg1 = new Regex(@"[^<^>]+");
                     //Match textMatch1 = textReg1.Match(temp);
                     //if (textMatch1 != null && textMatch1.Groups != null && textMatch1.Groups.Count > 0)
                     //{
                     //    result = textMatch1.Groups[0].Value;
                     //    sb.Append(result);
                     //}
                     Regex textReg = new Regex(@">.+<");
                     Match textMatch = textReg.Match(temp);
                     if (textMatch != null && textMatch.Groups != null && textMatch.Groups.Count > )
                     {
                         result = textMatch.Groups[].Value;
                         if (result.Length > )
                         {
                             result = result.Substring(, result.Length - );
                             sb.Append(result);
                         }
                     }                   
                 }
             }
 
             
 
             Console.WriteLine("解析出的结果:" + sb.ToString());
             Console.ReadLine();
         }
     }
 }