using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ConsoleApplication6

{

    public class Program

    {

        public static void Main(string[] args)

        {

            string fileName = @"D:\说明.txt";

            string result = GetMD5HashFromFile(fileName);

        }

        // <summary>

        /// 计算文件的MD5校验

        /// </summary>

        /// <param name="fileName"></param>

        /// <returns></returns>

        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 = ; i < retVal.Length; i++)

                {

                    sb.Append(retVal[i].ToString("x2"));

                }

                return sb.ToString();

            }

            catch (Exception ex)

            {

                throw new Exception("GetMD5HashFromFile() fail,error:" + ex.Message);

            }

        }

    }

}