What does Return myVar != null actually mean?

Question

Resharper is a great tool, but it sometimes confuses me as to what the suggested code really means. I have this code:

private bool DoesUserExists()
{
    var user = De.Users.FirstOrDefault(u => u.Username == CurrentUser.Username);
    return user != null;
}

I originally had :

if(user == null)
    return false;
else
    return true;

But Resharper suggested the top code. However, that looks to me to be saying return user if it is not null. But the method only accepts a bool return and not a class.

So what does return user != null actually return when it is null and when it is not?

Answer 1

So what does return user != null actually return when it is null and when it is not

It simply evaluates the expression. If user is null it returns false and if user isn't null, it returns true.

Think of this as if you were assigning the result of the comparison to a local variable, and only then returning it:

bool isNotNull = user != null;
return isNotNull;

Or:

bool isNull = user == null;
return !isNull;

isNotNull would be true only iff the user variable is not null.

Semantically, it is identical to your if-else statement.