实现Base64编码与其它编码转换的类

    public class Base64Provider
    {
        private Base64Provider()
        {
        }
        /// <summary>
        /// 将其它编码的字符串转换成Base64编码的字符串
        /// </summary>
        /// <param name="source">要转换的字符串</param>
        /// <returns></returns>
        public static string EncodeBase64String(string source)
        {
            //如果字符串为空或者长度为0则抛出异常
            if (string.IsNullOrEmpty(source))
            {
                throw new ArgumentNullException("source", "不能为空。");
            }
            else
            {
                //将字符串转换成UTF-8编码的字节数组
                byte[] buffer = Encoding.UTF8.GetBytes(source);
                //将UTF-8编码的字节数组转换成Base64编码的字符串
                string result = Convert.ToBase64String(buffer);
                return result;
            }
        }
        /// <summary>
        /// 将Base64编码的字符串转换成其它编码的字符串
        /// </summary>
        /// <param name="result">要转换的Base64编码的字符串</param>
        /// <returns></returns>
        public static string DecodeBase64String(string result)
        {
            //如果字符串为空或者长度为0则抛出异常
            if (string.IsNullOrEmpty(result))
            {
                throw new ArgumentNullException("result", "不能为空。");
            }
            else
            {
                //将字符串转换成Base64编码的字节数组
                byte[] buffer = Convert.FromBase64String(result);
                //将字节数组转换成UTF-8编码的字符串
                string source = Encoding.UTF8.GetString(buffer);
                return source;
            }
        }
    }