Question

While answering a question i came upon this

StringCollection sc = new StringCollection();

sc.Add("Foo");

But this can be written as

StringCollection sc = new StringCollection() {"Foo"};

and this cannot be written

StringCollection sc = new StringCollection() {new string[] {"Foo"} };

That means Add method is called and AddRange is not.

How can i make a class that can have this functionality of having a default method called while creating its object?

Answer 1

It’s called a Collection Initializer. The class must implement IEnumerable and have a public Add method.

The class can have multiple Add methods, e.g.

public class MyCollection : IEnumerable
{
    public void Add(string item) { ... }

    public void Add(string[] items) { ... }

    ...
}