Sequence contains no elements error but I want to check for null

Question

I have the following problem:

public Boolean Exists(String userName)
{
    IRepository = new UserRepository();
    User user = userRepository.Fir         


        

Answer 1

Use FirstOrDefault instead of First. This will return null in the face of an empty collection.

IRepository<User> = new UserRepository();
User user = userRepository.FirstOrDefault(u => u.Name == userName);

Answer 2

Use .FirstOrDefault() to prevent that error

Answer 3

Try changing .First() to .FirstOrDefault().