C# 生成MD5编码方法（不同位数）

        /// <summary> 
        /// </summary> 
        /// <param name="strSource">待加密字串</param> 
        /// <returns>加密后的字串</returns> 
        public static string MD5Encrypt(string strSource)
        {
            return MD5Encrypt(strSource, 32);
        }

        /// <summary> 
        /// </summary> 
        /// <param name="strSource">待加密字串</param> 
        /// <param name="length">16或32值之一,其它则采用.net默认MD5加密算法</param> 
        /// <returns>加密后的字串</returns> 
        public static string MD5Encrypt(string strSource, int length)
        {
            byte[] bytes = Encoding.ASCII.GetBytes(strSource);
            byte[] hashValue = ((System.Security.Cryptography.HashAlgorithm)System.Security.Cryptography.CryptoConfig.CreateFromName("MD5")).ComputeHash(bytes);
            StringBuilder sb = new StringBuilder();
            switch (length)
            {
                case 16:
                    for (int i = 4; i < 12; i++)
                        sb.Append(hashValue[i].ToString("x2"));
                    break;
                case 32:
                    for (int i = 0; i < 16; i++)
                    {
                        sb.Append(hashValue[i].ToString("x2"));
                    }
                    break;
                default:
                    for (int i = 0; i < hashValue.Length; i++)
                    {
                        sb.Append(hashValue[i].ToString("x2"));
                    }
                    break;
            }
            return sb.ToString();
        }