public string Md5Encrypt(string str, string str2)
{
byte[] result = Encoding.Default.GetBytes((str+str2).Trim()); //tbPass为输入密码的文本框
MD5 md5 = new MD5CryptoServiceProvider();
byte[] output = md5.ComputeHash(result);
string retrueMd5 = BitConverter.ToString(output).Replace("-", "");
return retrueMd5;
}