C#獲取URL參數值（NameValueCollection）

在寫程序的時候，咱們常常須要對頁面進行傳參數，好比page?id=1234，那麼在page這個頁面中就直接能夠使用string id = Request.QueryString["id"]; 來獲取參數id的值1234了。這是一我的人都知道的基礎知識。

上面的方法：Request.QueryString，它會把傳入的URL進行分析，並把結果保存在一個鍵值（key value）的Collection中，咱們只要經過設置key值，就能夠返回這個key所對應的value了。

假設這個URL不是經過請求進來的，咱們是沒有辦法經過Request來獲取URL的參數值的，咱們是否能夠經過一個字符串string url = "http://www.google.com/page?id=1234"中分析出Collection[key]=value呢？並且不少時候咱們的URL的參數都是通過UrlEncode編碼的，這個編碼一般來講會是Encoding.UTF8或者Encoding.GetEncoding("gb2312")，須要提醒你的是：Baidu的URL是使用gb2312的，而Google是使用UTF8的。那對於傳入的字符串咱們如何確認是該使用gb2312仍是UTF8來解碼呢？

在Baidu或者Google搜索到相關的解決辦法中，你會看到這樣的說法，那就是經過正則表達式去匹配URL，例如：Regex urlRegex = new Regex(@"(?:^|\?|&)courseid=(\d*)(?:&|$)"); 可是我比較懷疑經過這個方法分析出來的數據完整性，它有辦法確保匹配出全部數據嗎？後來我想到了模擬Microsoft .NET Framework中Request的方法來解決這個問題。其實上面的string id = Request.QueryString["id"]; 也能夠寫成 System.Collections.Specialized.NameValueCollection col = Request.QueryString; string strID = col[」id」];因此讓咱們來構造這個NameValueCollection吧！

 

  private string ResultDataSign(string postData)    

     {      

       //string echostr = Var.SYS_OAUTH_VERIFY_CODE;  

           NameValueCollection nameValue = GetQueryString(postData);     

       StringBuilder builder = new StringBuilder();       

      if (nameValue != null)     

        {         

        int count = 0;       

          String[] sortedKeys = nameValue.AllKeys;   

              Array.Sort(sortedKeys);       

          foreach (String key in sortedKeys)        

         {            

         count++;            

         builder.Append(key + "=" + nameValue[key]);      

               if (count != nameValue.Count)         

            {            

             builder.Append("&");       

              }            

     }     

        }         

    return md5(builder.ToString()).ToLower();      

   }

        private string md5(String input)      

   {      

       MD5CryptoServiceProvider Md5 = new MD5CryptoServiceProvider();     

        return BitConverter.ToString(Md5.ComputeHash(Encoding.UTF8.GetBytes(input))).Replace("-", "");  

       }     

    public static NameValueCollection GetQueryString(string queryString)   

      {     

        return GetQueryString(queryString, null, true);   

      }

        /// <summary>   

      /// 將查詢字符串解析轉換爲名值集合.       

  /// </summary>  

       /// <param name="queryString"></param>    

     /// <param name="encoding"></param>     

    /// <param name="isEncoded"></param>   

      /// <returns></returns>  

       public static NameValueCollection GetQueryString(string queryString, Encoding encoding, bool isEncoded)    

     {          

   queryString = queryString.Replace("?", "");    

         NameValueCollection result = new NameValueCollection(StringComparer.OrdinalIgnoreCase);       

      if (!string.IsNullOrEmpty(queryString))     

        {             

    int count = queryString.Length;       

          for (int i = 0; i < count; i++)       

          {        

             int startIndex = i;      

               int index = -1;           

          while (i < count)               

      {              

           char item = queryString[i];   

                      if (item == '=')      

                   {             

                if (index < 0)       

                      {       

                          index = i;        

                     }          

               }      

                   else if (item == '&')          

               {             

                break;          

               }        

                 i++;    

                 }       

              string key = null;        

             string value = null;   

                  if (index >= 0)    

                 {     

                    key = queryString.Substring(startIndex, index - startIndex);     

                    value = queryString.Substring(index + 1, (i - index) - 1);     

                }         

            else       

              {            

             key = queryString.Substring(startIndex, i - startIndex);     

                }       

              if (isEncoded)              

       {                   

      result[MyUrlDeCode(key, encoding)] = MyUrlDeCode(value, encoding);     

                }     

                else      

               {         

                result[key] = value;     

                }          

           if ((i == (count - 1)) && (queryString[i] == '&'))  

                   {         

                result[key] = string.Empty;         

            }          

       }      

       }        

     return result;   

      }    

     /// <summary>   

      /// 解碼URL.  

       /// </summary>  

       /// <param name="encoding">null爲自動選擇編碼</param>

        /// <param name="str"></param>   

      /// <returns></returns>     

    public static string MyUrlDeCode(string str, Encoding encoding)      

   {      

       if (encoding == null)    

         {          

       Encoding utf8 = Encoding.UTF8;                 //首先用utf-8進行解碼             

                        string code = HttpUtility.UrlDecode(str.ToUpper(), utf8);                 //將已經解碼的字符再次進行編碼.     

            string encode = HttpUtility.UrlEncode(code, utf8).ToUpper();       

          if (str == encode)       

              encoding = Encoding.UTF8;     

            else               

      encoding = Encoding.GetEncoding("gb2312");   

          }        

     return HttpUtility.UrlDecode(str, encoding);    

     }

用到System.web的命名空間