C# base64编码、解码

public class TransferCode
    {
        #region base-64编码、解码

        /// <summary>
        /// BASE64编码
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static string Base64Encode(string s)
        {
            try
            {
                s = Convert.ToBase64String(Encoding.Default.GetBytes(s));
                return Convert.ToBase64String(Encoding.Default.GetBytes(s));
            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// BASE64解码
        /// </summary>
        /// <param name="s"></param>
        /// <param name="encode"></param>
        /// <returns></returns>
        public static string Base64Decode(string s)
        {
            try
            {
                s = Encoding.Default.GetString(Convert.FromBase64String(s));
                return Encoding.Default.GetString(Convert.FromBase64String(s));
            }
            catch
            {
                return null;
            }
        }

        #endregion

        #region url编码、解码
        /// <summary>
        /// URL编码
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static string UrlEncode(string s)
        {
            return System.Web.HttpUtility.UrlEncode(s);
        }
        /// <summary>
        /// URL解码
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static string UrlDecode(string s)
        {
            return System.Web.HttpUtility.UrlDecode(s);
        }
        #endregion

        /// <summary>
        /// <summary>
        /// 字符串转Unicode
        /// </summary>
        /// <param name="source">源字符串</param>
        /// <returns>Unicode编码后的字符串</returns>
        public static string String2Unicode(string source)
        {
            byte[] bytes = Encoding.Unicode.GetBytes(source);
            StringBuilder stringBuilder = new StringBuilder();
            for (int i = 0; i < bytes.Length; i += 2)
            {
                stringBuilder.AppendFormat("\u{0}{1}", bytes[i + 1].ToString("x").PadLeft(2, '0'), bytes[i].ToString("x").PadLeft(2, '0'));
            }
            return stringBuilder.ToString();
        }
    }