把dictionary所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串

         /// <summary>
        /// 把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串，并对参数值做urlencode
        /// </summary>
        /// <param name="dicArray">需要拼接的数组</param>
        /// <param name="code">字符编码</param>
        /// <returns>拼接完成以后的字符串</returns>
        public static string CreateLinkStringUrlencode(Dictionary<string, string> dicArray, Encoding code = null)
        {
            code = code ?? Encoding.UTF8;
            StringBuilder prestr = new StringBuilder();
            foreach (KeyValuePair<string, string> temp in dicArray)
            {
                prestr.Append(temp.Key + "=" + HttpUtility.UrlEncode(temp.Value ?? "null", code) + "&");
            }
            //去掉最後一個&字符
            int nLen = prestr.Length;
            prestr.Remove(nLen - 1, 1);
            return prestr.ToString();
        }