Event and delegate contravariance in .NET 4.0 and C# 4.0

Question

While investigating this question I got curious about how the new covariance/contravariance features in C# 4.0 will affect it.

In Beta 1, C# seems to disagree with t

Answer 1

I just had to fix this in my application. I did the following:

// variant delegate with variant event args
MyEventHandler<(object sender, IMyEventArgs a)

// class implementing variant interface
class FiresEvents : IFiresEvents
{
    // list instead of event
    private readonly List> happened = new List>();

    // custom event implementation
    public event MyEventHandler Happened
    {
        add
        {
            happened.Add(value);
        }
        remove
        {
            happened.Remove(value);
        }
    }

    public void Foo()
    {
        happened.ForEach(x => x.Invoke(this, new MyEventArgs(t));
    }
}

I don't know if there are relevant differences to regular multi-cast events. As far as I used it, it works ...

By the way: I never liked the events in C#. I don't understand why there is a language feature, when it doesn't provide any advantages.