How do I use HashSet with custom objects in C#?

How do I use HashSet with custom objects in C#?

To use a HashSet with custom objects in C#, you need to override the Equals and GetHashCode methods in your class.

Can you show me an example of a custom object?

Sure! Here's a simple example:

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }

    public override bool Equals(object obj)
    {
        return obj is Person person && Name == person.Name && Age == person.Age;
    }

    public override int GetHashCode()
    {
        return HashCode.Combine(Name, Age);
    }
}

How do I add instances of this Person class to a HashSet?

You can add instances like this:

HashSet<Person> people = new HashSet<Person>();
people.Add(new Person { Name = "Alice", Age = 30 });
people.Add(new Person { Name = "Bob", Age = 25 });

What happens if I try to add a duplicate?

If you try to add a duplicate, the HashSet will not add it and will return false.