Question

I would like to know if there is some way to cast method group, anonymous method or lambda expression to System.Delegate without knowing exact delegate type, like

var d = ()=>{};
dynamic d = ()=>{};
Delegate d = ()=>{};

I need a way that would work for any method with any parameters and return type and not using reflection.
Thanks for your answers.

Answer 1

No it is not possible, because a delegate must have a single defined type, but multiple delegates can have the same signature. This makes the delegate type ambiguous – the compiler would have no way of robustly selecting an appropriate type in such a statement. Note that delegate instances of matching-signatures but different types are not interchangeable. For example, is:

i => (i % 2) == 0

A Func<int,bool>, or a Predicate<int> ? Or something else? Note that the number of generic arts is irrelevant; an Action and ThreadStart and MethodInvoker are all just void non-generic parameterless delegates.

Additionally, there’s an added complication / ambiguity because lambdas can also be compiled to expression trees, not just delegates:

Func<int, bool> x = i => (i % 2) == 0;
Expression<Func<int, bool>> y = i => (i % 2) == 0;

Expression trees are radically different to delegates.