Question

I am currently using the following code within my controller:

Instructor instructor = db.Instructors.FirstOrDefault(
    o => o.UserName == User.Identity.Name);

to select someone by username. My understanding is that I will have trouble using “FirstOrDefault()” if I have user’s with similar user names (i.e. searching for “MrUser” when I have users named “MrUserOne” “MrUserTwo” and “MrUser” may yield “MrUserOne” because it was the ‘first’ search result to show up), If I am correct in my understanding of future difficulties with “FirstOrDefault,” what should I use in it’s place?

Or am I wrong in my understanding of how FirstOrDefault will work?

Answer 1

It appears you don’t quite understand how the == operator works in this scenario. Assuming the UserName and Name values are both string then == will do an exact ordinal match. The name "MrUser" won’t match "MrUserOne" at all. It will only match "MrUser".

That being said this code will return the first user whose Name value exactly matches o.UserName or null if none do.