Question

I have an object that can be a list of different enum types or non-enum types (normal class instances).

To verify if object is a list is easy:

myobject is IList

Now I can verify the type of list’s elements:

(myobject as IList)[0].GetType().IsEnum

But how to verify if my list’s elements are enums IF I have no elements yet ?

if (myobject is IList)
{ 
    if ((myobject as IList).Count > 0)
    {
        if ((myobject as IList)[0].GetType().IsEnum)
            return true;
    }
    else
    {
        // how to check if the list is enum list here ?
    }
}

Answer 1

An IList can contain whatever type it wants, so if you don’t have any contents you have no way of checking. If you actually have a generic type to start with you can check by using the GetGenericArguments method of Type. (GetInterface added in case you have something that’s implementing IList but doesn’t have the IList type as it’s first generic argument).

 myobject.GetType().GetInterface("System.Collections.Generic.IList").GetGenericArguments()[0].IsEnum