winfrom和正则表达式高手进来看下，就差一点小问题了！！！

Question

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Text.RegularExpressions;
using System.Web;namespace WindowsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }       
        private void button1_Click(object sender, EventArgs e)
        {
                        if(textBox1.Text!=""){
                FileStream fileOpen = new FileStream(textBox1.Text,FileMode.Open);
                webBrowser1.DocumentStream = fileOpen;
                
               StreamReader sr = new StreamReader(fileOpen); 
               string strHtml = sr.ReadToEnd();
               strHtml = NoHtml.Ubb(textBox1.Text);
               webBrowser1.DocumentText = strHtml;  
            }                   
            
        }        private void button2_Click(object sender, EventArgs e)
        {
            OpenFileDialog open = new OpenFileDialog();
            open.RestoreDirectory = true;
            open.FilterIndex = 1;
            open.Filter = "文本文件(*.txt)|*.*|html文件(*html)|*.html|所有文件|*.*";
            open.InitialDirectory = "c:\\";
            if(open.ShowDialog()==DialogResult.OK){
                textBox1.Text = open.FileName;
            }
        }        private void Form1_Load(object sender, EventArgs e)
        {     }
            }
        }上面这是我from中的！！！using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows.Forms;
using System.Web;
using System.IO;
namespace WindowsApplication3
{
 public   class NoHtml
    {
     public static string Ubb(string Htmlstring)
     {         Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);
         Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
         Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\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("\r\n", "");
         Htmlstring=HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();
         return Htmlstring;        }     }
}
这个是单独创建个类写的正则表达式！
现在不懂的事，我现在运行就出现：Htmlstring=HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();未将对象引用设置到对象的实例，实在解决不明白了！！有高手帮答下吗！

Answer 1

Htmlstring=HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim(); 你是winform的程序，怎么可能会有 HttpComtext呢？
你的 HttpContext.Current就是个NULL要使用HtmlEncode，可以用 System.Web.HttpServerUtility.HtmlEncode

Answer 2

.....WINFOR下使用 引用System.Web.dll  Htmlstring = System.Web.HttpUtility.HtmlEncode(Htmlstring).Trim();

Answer 3

解决方案下的“引用”-> 右键 -> 添加引用 -> System.Web