Sorting a List of Custom Objects by Year with Complex Criteria in C#
Does anyone know how to I'm refactoring my project and I've been working on this all day and I'm sure I'm missing something obvious here, but Hey everyone, I'm running into an issue that's driving me crazy... I'm working with a list of custom objects representing books, which have properties like `Title`, `Author`, and `PublicationDate`. I want to sort this list primarily by the year of publication in descending order, but if two books were published in the same year, I need to sort them alphabetically by their title. I'm using .NET 6 and have tried using a custom `IComparer`, but I'm getting unexpected results when two books share the same publication year. Here’s the code I’ve implemented: ```csharp public class Book { public string Title { get; set; } public string Author { get; set; } public DateTime PublicationDate { get; set; } } public class BookComparer : IComparer<Book> { public int Compare(Book x, Book y) { // First compare by year in descending order int yearComparison = y.PublicationDate.Year.CompareTo(x.PublicationDate.Year); if (yearComparison == 0) { // Then compare by title alphabetically return string.Compare(x.Title, y.Title); } return yearComparison; } } var books = new List<Book> { new Book { Title = "C# in Depth", Author = "Jon Skeet", PublicationDate = new DateTime(2019, 2, 1) }, new Book { Title = "C# 8.0 in a Nutshell", Author = "Joseph Albahari", PublicationDate = new DateTime(2020, 6, 1) }, new Book { Title = "The Pragmatic Programmer", Author = "Andrew Hunt", PublicationDate = new DateTime(2020, 11, 1) }, new Book { Title = "Effective C#", Author = "Bill Wagner", PublicationDate = new DateTime(2019, 2, 1) } }; books.Sort(new BookComparer()); ``` After sorting, I'm expecting the `books` list to be ordered first by the publication year and then alphabetically by title for books published in the same year. However, I noticed that the books published in 2019 are not sorted alphabetically as expected. Instead, `C# in Depth` appears after `Effective C#`. I’ve checked my `Compare` method, and it seems correct as per my logic. What could I be missing here? Is there a more efficient way to achieve this sorting without using a custom comparer? I'm working on a API that needs to handle this. Any help would be greatly appreciated! How would you solve this? My team is using C# for this service. I'd really appreciate any guidance on this. This is part of a larger mobile app I'm building. Has anyone dealt with something similar? The project is a microservice built with C#.