Determine if collection is of type IEnumerable

Question

How to determine if object is of type IEnumerable ?

Code:

namespace NS {
    class Program {
        static IEnumerable GetInts()         


        

Answer 1

If you mean the collection, then just as:

var asEnumerable = i as IEnumerable;
if(asEnumerable != null) { ... }

However, I'm assuming (from the example) that you have a Type:

The object will never be "of" type IEnumerable - but it might implement it; I would expect that:

if(typeof(IEnumerable).IsAssignableFrom(type)) {...}

would do. If you don't know the T (int in the above), then check all the implemented interfaces:

static Type GetEnumerableType(Type type) {
    if (type.IsInterface && type.GetGenericTypeDefinition() == typeof(IEnumerable<>))
        return type.GetGenericArguments()[0];
    foreach (Type intType in type.GetInterfaces()) {
        if (intType.IsGenericType
            && intType.GetGenericTypeDefinition() == typeof(IEnumerable<>)) {
            return intType.GetGenericArguments()[0];
        }
    }
    return null;
}

and call:

Type t = GetEnumerableType(type);

if this is null, it isn't IEnumerable for any T - otherwise check t.