.NET过滤html标签

在写程序的时候我们常常要对用户输入的文本进行检查，常见的就是对html标签的过滤！这个很重要。那么怎么处理呢，看完下面代码你就知道了！
///   <summary>
///   去除HTML标记
///   </summary>
///   <param   name="NoHTML">包括HTML的源码   </param>
///   <returns>已经去除后的文字</returns>
public static string NoHTML(string Htmlstring)
{
//删除脚本
Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "",
    RegexOptions.IgnoreCase);
//删除HTML
Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"([ ])[s]+", "",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", """,
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", "   ",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "xa1",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "xa2",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "xa3",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "xa9",
    RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&#(d+);", "",
    RegexOptions.IgnoreCase);

Htmlstring.Replace("<", "");
Htmlstring.Replace(">", "");
Htmlstring.Replace(" ", "");
Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();

return Htmlstring;
}

/**/ ///提取HTML代码中文字的C#函数
///   <summary>
///   去除HTML标记
///   </summary>
///   <param   name="strHtml">包括HTML的源码   </param>
///   <returns>已经去除后的文字</returns>
using System;
using System.Text.RegularExpressions;
public class StripHTMLTest
{
public static void Main()
{
    string s = StripHTML(
      "<HTML><HEAD><TITLE>我的博客 </TITLE></HEAD><BODY>faddfs欢迎您</BODY></HTML>");
    Console.WriteLine(s);
}

public static string StripHTML(string strHtml)
{
    string[]aryReg =
    {
      @"<script[^>]*?>.*?</script>",

@"<(/s*)?!?((w+:)?w+)(w+(s*=?s*(([""'])(\["
        "'tbnr]|[^7])*?7|w+)|.{0})|s)*?(/s*)?>", @"([ ])[s]+", @
        "&(quot|#34);", @"&(amp|#38);", @"&(lt|#60);", @"&(gt|#62);", @
        "&(nbsp|#160);", @"&(iexcl|#161);", @"&(cent|#162);", @"&(pound|#163);",
        @"&(copy|#169);", @"&#(d+);", @"-->", @"<!--.* "
    };

    string[]aryRep =
    {
      "", "", "", """, "&", "<", ">", "   ", "xa1", //chr(161),
      "xa2", //chr(162),
      "xa3", //chr(163),
      "xa9", //chr(169),
      "", " ", ""
    };

    string newReg = aryReg[0];
    string strOutput = strHtml;
    for (int i = 0; i < aryReg.Length; i++)
    {
      Regex regex = new Regex(aryReg[i], RegexOptions.IgnoreCase);
      strOutput = regex.Replace(strOutput, aryRep[i]);
    }
    strOutput.Replace("<", "");
    strOutput.Replace(">", "");
    strOutput.Replace(" ", "");
    return strOutput;
}
}

//使用静态方法移除HTML标签
#region
///移除HTML标签
/**/ ///   <summary>
///   移除HTML标签
///   </summary>
///   <param   name="HTMLStr">HTMLStr</param>
public static string ParseTags(string HTMLStr)
{
return System.Text.RegularExpressions.Regex.Replace(HTMLStr, "<[^>]*>", "");
}

#endregion

///   取出文本中的图片地址
#region
///   取出文本中的图片地址
/**/ ///   <summary>
///   取出文本中的图片地址
///   </summary>
///   <param   name="HTMLStr">HTMLStr</param>
public static string GetImgUrl(string HTMLStr)
{
string str = string.Empty;
string sPattern = @"^<imgs+[^>]*>";
Regex r = new Regex(@"<imgs+[^>]*s*srcs*=s*([']?)(?<url>S+)'?[^>]*>",
    RegexOptions.Compiled);
Match m = r.Match(HTMLStr.ToLower());
if (m.Success)
    str = m.Result("${url}");
return str;
}

#endregion