Search⌘ K
AI Features
Home
Courses
Getting Started with LINQ in C#

Replace a Set of Choices with FirstOrDefault

Explore how to refactor multiple conditional checks into a streamlined approach using LINQ's FirstOrDefault method. Understand replacing chained if statements with arrays of functions and applying the null-coalescing operator to simplify logic when selecting values from various sources.

We'll cover the following...

How to Refactor a chain of conditionals with FirstOrDefault

When we need to find a value between multiple choices, we write consecutive if statements to check for a valid result every time.

For example, let’s find the next film to watch from one of three sources: the latest releases in cinemas, our friends’ recommendations, and the all-time classics.

C#
using System;
namespace MovieCatalog
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            // Let's find the next movie to watch
            var nextMovie = FindLastestRelease();
            if (nextMovie == null)
                nextMovie = FindFriendsRecommendation();
            if (nextMovie == null)
                nextMovie = FindClassic();
            if (nextMovie != null)
                Console.WriteLine($"{nextMovie.Name}");
            else
                Console.WriteLine("No movies to watch");
        }
        private static Movie FindLastestRelease()
        {
            return null;
        }
        private static Movie FindFriendsRecommendation()
        {
            return new Movie
            {
                Name = "Taxi Driver",
                Genre = Genre.Drama
            };
        }
        private static Movie FindClassic()
        {
            return new Movie
            {
                Name = "Spirited Away",
                Genre = Genre.Fantasy
            };
        }
    }
    internal class Movie
    {
        public string Name { get; set; }
        public Genre Genre { get; set; }
    }
    internal enum Genre
    {
        Comedy,
        Action,
        Drama,
        War,
        Fantasy
    }
}

Notice that after we called a ...