Question

What are the differences between these two classes? Which is preferable?

class MulticastExample
{
    delegate void ME();

    ME me;

    public MulticastExample()
    {
        ME a = new ME(() => Console.WriteLine("A"));
        ME b = new ME(() => Console.WriteLine("B"));

        me = a + b;
    }

    public void Run()
    {
        me();
    }
}

–

class ListExample
{
    delegate void LE();

    List<LE> le = new List<LE>();

    public ListExample()
    {
        LE a = new LE(() => Console.WriteLine("A"));
        LE b = new LE(() => Console.WriteLine("B"));

        le.Add(a);
        le.Add(b);
    }

    public void Run()
    {
        foreach (var x in le)
        {
            x();
        }
    }
}

Answer 1

With MulticastExample,a single call to me would call all the methods subscribed to it.So a and b would be called through a single call to me

With ListExample you would have to call each of the delegates individually.So you would have to individually invoke a and b which you are doing in the foreach loop

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If a and b are going to refer to a single method of the same signature then ListExample is redundant.You should use MulticastExample.