过滤HTML 字符串,原来字符串

using System;
//using System.Text;
namespace SCard
{
/// <summary>
/// CleanString 的摘要说明。
/// </summary>
public sealed class CleanString
{
  public static string htmlInputText( string inputString )//HTML过滤输入字符串
  {
   if ((inputString != null) && (inputString != String.Empty ))
   {
    inputString = inputString.Trim();
    inputString = inputString.Replace("'","&quot;");
    inputString = inputString.Replace("<","&lt;");
    inputString = inputString.Replace(">","&gt;");
    inputString = inputString.Replace(" ","&nbsp;");
    inputString = inputString.Replace("\n","<br>");
    return inputString.ToString();
   }
   return "";
  }
  public static string htmlOutputText( string inputString )//HTML还原字符串
  {
   if ((inputString != null) && (inputString != String.Empty ))
   {
    inputString = inputString.Trim();
    inputString = inputString.Replace("&quot;","'");
    inputString = inputString.Replace("&lt;","<");
    inputString = inputString.Replace("&gt;",">");
    inputString = inputString.Replace("&nbsp;"," ");
    inputString = inputString.Replace("<br>","\n");
    return inputString.ToString();
   }
   return "";
  }
}
}