How to use Func<T, bool> as a parameter for Func<object, bool>?

Question

I have a method with declaration like this:

public void OriginalMethod(Func<object,bool> selector)

And I would like to call it from generic method, that has declaration like this:

public void GenericMethod<T>(Func<T, bool> selector)

How do I do that?

Answer 1

You can't pass the selector directly to OriginalMethod : it expects a method that accepts any object , but a Func<T, bool> accepts only an object of type T .

Of course, you can cheat:

OriginalMethod(o => selector((T)o));

But if OriginalMethod calls the method with an object that is not convertible to T, it will fail...

Answer 2

You need to create a Func<object, bool> that calls the typed one passed in.

public void GenericMethod<T>(Func<T, bool> selector)
{
    Func<object, bool> untypedSelector = (object obj) => selector((T)obj);

    OriginalMethod(untypedSelector);
}

Either like the above, or a one-liner like Marc's answer .

Answer 3

OriginalMethod(arg => selector((T)arg));