Collecting types that implement a particular interface without casting?

Question

Basically I wanna know if all the types in a particular namespace implements a particular interface like IEnumerable.

I know I can do:

foreach type ...
    if type is IEnumerable
        ...

But I don't wanna cast the type just to query if it implements an interface, because the cast will be thrown away either way.

Answer 1

Using the is operator is not a cast, it is a test, which sounds like what you want. Type casting in C# is done either using the forced casting operator (name?) like so:

((IEnumerable)someCollection)

or the safe casting operator:

someCollection as IEnumerable

Answer 2

Assuming I've read you correctly, you want a list of types in an enumeration that implement an particular interface or supertype. Perhaps Enumerable.OfType(this IEnumerable source) is useful?

var enumerables = myListOfThingsToCheck.OfType<IEnumerable>();

Answer 3

I think this will work also if you'd rather use lambda syntax.

var enumerables=Assembly.GetExecutingAssembly().GetTypes().Where(t => t.Namespace == "YOUR NAMESPACE HERE").OfType<IEnumerable>();