Hey Reader,

Today, I want to show you something important about casting objects in C#. We’ll talk about the difference between casting a single object and a list of objects.

What’s the Problem?

Imagine you have a game with characters. We have a Character class that implements an ICharacter interface. Here's what that looks like:

Single Object Casting

We have a method to get a single character by its ID. Here’s how it looks:

When we run this method, it works because C# knows that Character implements ICharacter, so it can cast it automatically.

List of Objects Casting

Now, let’s get a list of characters:

Here’s the problem: You can't return a List as a List directly because the compiler doesn't know how to do that. We have to explicitly cast each Character to ICharacter using LINQ’s Select method.

How to Fix It

To fix this, we use LINQ’s Select method to cast each Character to ICharacter:

This code goes through each Character in the list and casts it to ICharacter.

Summary

1. Single Object: C# can cast a single Character to ICharacter automatically.
2. List of Objects: You need to manually cast each Character to ICharacter.

See it in Action

Check out the full tutorial on YouTube to see this in action 👇

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Conclusion

I hope this helps you understand how to cast objects in C#. Remember, single objects can be cast implicitly, but lists need explicit casting.

Happy coding!

Take care,

Patrick

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