C#获取文件MD5值或者字符串MD5值方法

1、第一种计算文件MD5值方法       

         /// 

        /// 获取文件的MD5值
        /// 
        /// 文件全路径
        /// 
		public static string GetMD5HashFromFile(string fileName)
         {
             try
             {
                 FileStream file = new FileStream(fileName, FileMode.Open);
                 System.Security.Cryptography.MD5 md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
                 byte[] retVal = md5.ComputeHash(file);
                 file.Close();
 
                 StringBuilder sb = new StringBuilder();
             for (int i = 0; i < retVal.Length; i++)
             {
                sb.Append(retVal[i].ToString("x2"));
             }
                return sb.ToString();
             }
             catch (Exception ex)
             {
                throw new Exception("GetMD5HashFromFile() fail,error:" + ex.Message);
             }
         }

2、第二种获取文件MD5值的方法

        /// 

        /// 计算文件的MD5值
        /// 
        /// 文件全路径
        /// 
        public string MD5Value(String filepath)
        {
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] md5ch;
            using (FileStream fs = File.OpenRead(filepath))
            {
                md5ch = md5.ComputeHash(fs);
            }
            md5.Clear();
            string strMd5 = "";
            for (int i = 0; i < md5ch.Length - 1; i++)
            {
                strMd5 += md5ch[i].ToString("x").PadLeft(2, '0');
            }
            return strMd5;
        }

3、计算字符串MD5值方法

        /// 

        /// 计算字符串的MD5值
        /// 
        /// 字符串
        /// 
        public string GetMD5(string sDataIn)
        {
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] bytValue, bytHash;
            bytValue = System.Text.Encoding.UTF8.GetBytes(sDataIn);
            bytHash = md5.ComputeHash(bytValue);
            md5.Clear();
            string sTemp = "";
            for (int i = 0; i < bytHash.Length; i++)
            {
                sTemp += bytHash[i].ToString("X").PadLeft(2, '0');
            }
            return sTemp.ToLower();
        }