过滤html标签

string notice = Request.Form["notice"];
StringBuilder sb =new StringBuilder(HttpUtility.HtmlEncode(notice));
//允许<b> 和 <i>
sb.Replace("&lt;b&gt;", "<b>");
sb.Replace("&lt;/b&gt;", "");
sb.Replace("&lt;i&gt;", "<i>");
sb.Replace("&lt;/i&gt;", "");
notice = sb.ToString();

protected string str = "<table><tr><td>sdasasdsdd</td></tr></table><br><p>sds</p><img id='img1' src='http://www.baidu.com/img/baidu_logo.gif' width='100' height='50' alt=''>aaassss<br><img src='http://www.baidu.com/img/baidu_logo.gif' width='100' height='50' alt=''> 说是道 ";

    protected void Page_Load(object sender, EventArgs e)
    {

        //string regexstr = @"<[^>]*>";    //去除所有的标签

        //@"<script[^>]*?>.*?</script>" //去除所有脚本，中间部分也删除
        
        // string regexstr = @"<img[^>]*>";   //去除图片的正则

       // string regexstr = @"<(?!br).*?>";   //去除所有标签，只剩br

        // string regexstr = @"<table[^>]*?>.*?</table>";   //去除table里面的所有内容

        string regexstr = @"<(?!img|br|p|/p).*?>";   //去除所有标签，只剩img,br,p
  
        str = Regex.Replace(str, regexstr, string.Empty, RegexOptions.IgnoreCase);

    }

 

 

 

 

 

ASP.NET 去除所有HTML标记 < type="text/javascript">function StorePage(){d=document;t=d.selection?(d.selection.type!='None'?d.selection.createRange().text:''):(d.getSelection?d.getSelection():'');void(keyit=window.open('http://www.365key.com/storeit.aspx?t='+escape(d.title)+'&u='+escape(d.location.href)+'&c='+escape(t),'keyit','scrollbars=no,width=475,height=575,left=75,top=20,status=no,resizable=yes'));keyit.focus();}
注意:需要先using  System.Text.RegularExpressions;  

/**////   <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,@"([\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;  
  }

/**////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>中国石龙信息平台</TITLE&amp;gt;</HEAD><BODY>faddfs龙信息平台</BODY></HTML>");  
          Console.WriteLine(s);  
      }  
   
      public   static   string   StripHTML(string   strHtml){  
          string   []   aryReg   ={  
                      @"<script[^>]*?>.*?</script>",  
   
                      @"<(\/\s*)?!?((\w+:)?\w+)(\w+(\s*=?\s*(([""'])(http://www.cnblogs.com/xchit/admin/file://[%22%22'tbnr]%7c[%5e/7])*?\7|\w+)|.{0})|\s)*?(\/\s*)?>",  
                      @"([\r\n])[\s]+",  
                      @"&(quot|#34);",  
                      @"&(amp|#38);",  
                      @"&(lt|#60);",  
                      @"&(gt|#62);",    
                      @"&(nbsp|#160);",    
                      @"&(iexcl|#161);",  
                      @"&(cent|#162);",  
                      @"&(pound|#163);",  
                      @"&(copy|#169);",  
                      @"&#(\d+);",  
                      @"-->",  
                      @"<!--.*\n"  
                    };  
   
          string   []   aryRep   =   {  
                        "",  
                        "",  
                        "",  
                        "\"",  
                        "&",  
                        "<",  
                        ">",  
                        "   ",  
                        "\xa1",//chr(161),  
                        "\xa2",//chr(162),  
                        "\xa3",//chr(163),  
                        "\xa9",//chr(169),  
                        "",  
                        "\r\n",  
                        ""  
                      };  
   
          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("\r\n","");  
          return   strOutput;  
      }  
  }

写一个静态方法  
  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   =   @"^<img\s+[^>]*>";  
                          Regex   r   =   new   Regex(@"<img\s+[^>]*\s*src\s*=\s*([']?)(?<url>\S+)'?[^>]*>",  
                                  RegexOptions.Compiled);  
                          Match   m   =   r.Match(HTMLStr.ToLower());  
                          if   (m.Success)  
                                  str   =   m.Result("${url}");  
                          return   str;  
                  }  
   
                  #endregion