//计算字符串的MD5值         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();         }                 //计算文件的MD5值         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;         }