C#•2y ago

❔ How to handle null in Interface

I'm trying to learn .Net Core MVC and I'm following a course where the following code gives a warning of a possible null reference return. Can some one tell me how to best handle this?

public async Task<T> GetByIdAsync(int id)
        {
            var result = await _context.Set<T>().FirstOrDefaultAsync(n => n.Id == id);

            return result; 
        }

18 Replies

Thinker•2y ago

Return Task<T?> instead

Angius•2y ago

(and don't use generic repositories on top of EF, for all that is holy, do not)

1grumpydevOP•2y ago

I'm not quite following you regarding "Return Task<T?>.

Thinker•2y ago

Change the return type from Task<T> to Task<T?>

1grumpydevOP•2y ago

Geez, I feel stupid. Thanks! Also regarding the other comment, so it is a bad practice to use a generic repository as it is being used?

Thinker•2y ago

(read up on nullable reference types if you want more information about what the ? does)

Angius•2y ago

EF's DbContext already implements Unit of Work, and each DbSet is already a repository Wrapping a repository in a repository makes about as much sense as

public static class MyConsole
{
    public static void WriteLine(string line)
    {
        Console.WriteLine(line);
    }
}

public static class MyConsole
{
    public static void WriteLine(string line)
    {
        Console.WriteLine(line);
    }
}

Denis•2y ago

Generic repository is a redundant abstraction. I've tried implementing it, based on a Udemy course. Didn't see a real benefit

Angius•2y ago

If the course demands it, sure, proceed with the course

Denis•2y ago

Only made my code more complicated

Angius•2y ago

But it's a lot of code that just does nothing

1grumpydevOP•2y ago

Ah, I see yeah in this Udemy course the instructor was trying to demonstrate separate of concern by doing it like this instead of just handling it in the controller Thanks for the explanation

Monsieur Wholesome•2y ago

But what if you want to move away from the EF dependency Kappa

Angius•2y ago

Then you'll have to rewrite a lot of code anyway ¯\_(ツ)_/¯

Monsieur Wholesome•2y ago

Not if you apply your on repo pattern

Klarth•2y ago

Then all you need to do is rewrite all of your queries from Linq to SQL. Really minor change. kappa

Monsieur Wholesome•2y ago

At least it would all be in the very few classes of your repositories, centralized to the very few intended places, and not scattered all over your 21287 thousand file project Kappa

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

Gaming

Programming

❔ How to handle null in Interface