Question

I have the following piece of code in my DataModel.cs class:

    public User ValidateUser(string Username, string Password)
    {
        DataContext db = new DataContext();

                var query = from u in db.Users where (u.Username == Username && u.Password == Password) select u;

                if (query.Count() != 0)
                {
                    return query.First();
                }
                else
                {
                    return new User { UserID = -1 };
                }
    }

I have a login class calling this on my DataModel, checking to see if a user is valid. If the user is valid than I want to have a reference to that “logged-in” user in my login class (which is why ValidateUser returns a user object).

Right now, if that user doesn’t exist or the password is wrong, I simply return an empty User object with the id set to -1 to flag it as being not a real user.

Is this bad practice?

How should I handle this case? If ValidateUser just returned a bool it wouldn’t be a problem but because I also need a reference to that user I don’t know how else to do it.

Answer 1

IMO, this is bad practice, because it is implicit. If nothing is returned, the method should return null. This is self-explanatory.

Or, if it needs to be handled completely different as the normal case or needs additional information, you could consider to throw an exception.