How to make inline array initialization work like e.g. Dictionary initialization?

Question

Why is it possible to initialize a Dictionary like this:

var dict = new Dictionary() { 
    { \"key1\", 1 },
    { \"         


        

Answer 1

Thanks to multiple answerers for pointing out that the Add method is the magical thing secret sauce that makes the initialization syntax work. So I could achieve my goal by inheriting the class in question (KeyValuePair):

public class InitializableKVPs : IEnumerable>
{
    public void Add(T1 key, T2 value) 
    {
        throw new NotImplementedException();
    }

    public IEnumerator>  GetEnumerator()
    {
        throw new NotImplementedException();
    }

    IEnumerator  IEnumerable.GetEnumerator()
    {
        throw new NotImplementedException();
    }
}

This now is accepted by the compiler:

var kvps = new InitializableKVPs {
    { "key1", 1 },
    { "key2", 2 }
};

Edit: Philip Daubmeier's answer has an actual, concise implementation of this.