Comparing generics: A “master-type” IEnumerable<

Question

I want to to compare typeof(IEnumerable<>) to the types of various specific classes of IEnumerable, e.g.

Compare(typeof(IEnumerable<>), typeof(IEnumerable<object>))   // should return true
Compare(typeof(IEnumerable<>), typeof(IEnumerable<int>))      // should return true
Compare(typeof(IEnumerable<>), typeof(IEnumerable<MyClass>))  // should return true
Compare(typeof(IEnumerable<>), typeof(IEnumerable))           // should return FALSE because IEnumerable is not the generic IEnumerable<> type

How can I do this? All common methods such as == or IsAssignableFrom return false for all above examples.

---

Probably not necessary for the question, but some background:

I'm writing a conversion class that convers an object into some other type. I'm using Attributes (XlConverts):

public class XlConvertsAttribute : Attribute
{
    public Type converts;
    public Type to;
}

to flag which type each methods converts into. One of my conversion methods converts an object into IEnumerable:

[XlConverts(converts = typeof(object), to = typeof(IEnumerable<>))]
    public static IEnumerable<T> ToIEnumerable<T>(object input)
    {
    // ....
}

Then I have a more general method

public static object Convert(object input, Type toType)
{
    // ...
}

Which uses reflection to get the method that has XlConverts.to == toType, so basically it reflects its own class to find the approrpaite conversion method given the desired target type.

now when I call Convert(input, typeof(IEnumerable)), it is supposed to find the method ToIEnumerable by reflection. But as I can only flag it with [XlConverts(to = typeof(IEnumerable<>)), and IEnumerable<> is not IEnumerable, it won't find this method.

I'm aware just using IEnumerable instead of IEnumerable<> would do the job here, but I explicitly need to use the generic IEnumerable<> because later on, I want to do further reflection and filter out all methods that convert into a generic type.

Thanks!

Answer 1

public static bool Compare(Type genericType, Type t)
{
    return t.IsGenericType && t.GetGenericTypeDefinition() == genericType;
}