C# 获取文件md5码值

 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 (System.Exception ex)
        {

            Debug.Log("错误信息："+ex);
            return null;
        }

    }