public static string GetMd5Hash(string pathName)  {      string strResult = "";      string strHashData = "";      byte[] arrbytHashValue;          System.IO.FileStream oFileStream = null;          System.Security.Cryptography.MD5CryptoServiceProvider oMD5Hasher = new System.Security.Cryptography.MD5CryptoServiceProvider();          try      {          oFileStream = new System.IO.FileStream(pathName.Replace("\\"", ""), System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.ReadWrite);              arrbytHashValue = oMD5Hasher.ComputeHash(oFileStream); //计算指定Stream 对象的哈希值              oFileStream.Close();              //由以连字符分隔的十六进制对构成的String，其中每一对表示value 中对应的元素；例如“F-2C-4A”              strHashData = System.BitConverter.ToString(arrbytHashValue);              //替换-          strHashData = strHashData.Replace("-", "");              strResult = strHashData;      }          catch (System.Exception ex)      {          Console.WriteLine(ex.Message);      }      return strResult;  }