C#实现UrlEncode (URL编码)

 public static string UrlEncode(string str)
         {
             StringBuilder sb = new StringBuilder();
             byte[] byStr = System.Text.Encoding.UTF8.GetBytes(str); //默认是System.Text.Encoding.Default.GetBytes(str)
             for (int i = ; i < byStr.Length; i++)
             {
                 sb.Append(@"%" + Convert.ToString(byStr[i], ));
             }

             return (sb.ToString());
         }