C# - Unexpected Behavior with LINQ When Grouping by Complex Types in .NET 6
I've looked through the documentation and I'm still confused about I'm integrating two systems and I'm relatively new to this, so bear with me... Quick question that's been bugging me - I'm encountering unexpected behavior when using LINQ to group a list of custom objects by a complex property in .NET 6... The data structure I'm working with is as follows: ```csharp public class Product { public int Id { get; set; } public string Name { get; set; } public Category ProductCategory { get; set; } } public class Category { public int CategoryId { get; set; } public string CategoryName { get; set; } } ``` I have a list of `Product` objects, and I am trying to group them by `ProductCategory`. Here's the LINQ query I've written: ```csharp var groupedProducts = products.GroupBy(p => p.ProductCategory); ``` However, I find that when I attempt to iterate through the `groupedProducts`, I'm getting an inconsistent number of groups. Specifically, if two products have the same `CategoryId` but different `CategoryName`, they are being treated as different categories. This is not what I expected since I believed LINQ would use the default equality comparison for the `Category` objects. To troubleshoot, I tried overriding `Equals` and `GetHashCode` in the `Category` class: ```csharp public override bool Equals(object obj) { if (obj is Category category) { return this.CategoryId == category.CategoryId; } return false; } public override int GetHashCode() { return CategoryId.GetHashCode(); } ``` I also confirmed that the `ProductCategory` is not null. After making these changes, I still observed the same grouping issue. Here’s the output I get when iterating through `groupedProducts`: ```csharp foreach (var group in groupedProducts) { Console.WriteLine($"Category ID: {group.Key.CategoryId}, Products Count: {group.Count()}"); } ``` This outputs distinct counts for categories that I expected to be grouped together. Am I missing something in how LINQ handles grouping by complex types in .NET 6? Any insights or best practices would be greatly appreciated. For context: I'm using C# on Linux. Is there a better approach? For context: I'm using C# on macOS. How would you solve this? I'm open to any suggestions. I'm working with C# in a Docker container on macOS. Thanks for your help in advance!