C# Dynamic Event Subscription

Question

How would you dynamically subscribe to a C# event so that given a Object instance and a String name containing the name of the event, you subscribe to that event and do some

Answer 1

This method adds to an event, a dynamic handler that calls a method OnRaised, passing the event parameters as an object array:

void Subscribe(object source, EventInfo ev)
{
    var eventParams = ev.EventHandlerType.GetMethod("Invoke").GetParameters().Select(p => Expression.Parameter(p.ParameterType)).ToArray();
    var eventHandler = Expression.Lambda(ev.EventHandlerType,
        Expression.Call(
            instance: Expression.Constant(this),
            method: typeof(EventSubscriber).GetMethod(nameof(OnRaised), BindingFlags.NonPublic | BindingFlags.Instance),
            arg0: Expression.Constant(ev.Name),
            arg1: Expression.NewArrayInit(typeof(object), eventParams.Select(p => Expression.Convert(p, typeof(object))))),
        eventParams);
    ev.AddEventHandler(source, eventHandler.Compile());
}

OnRaised has this signature:

void OnRaised(string name, object[] parameters);