Test the type is implements the interface or not. c#

I want to know the from the System.Type is implements the interface or not. But I want to handle the generic cases as well.

There is a question in SQ where the answer is highly rated, but for my case is not a solution, for some reason:

1. I do not have an instance of the object
2. I want to handle the special generic classes as well. e.g.: IDictionary<,>

so when I have an instance the code is sill not a solution, because i cannot write this:

  IDictionary<,> myTest = originalObject as IDictionary<,>

because the IDictionary<,> is not a valid type. What is best way to tell the System.Type is implements an interface or not.

---

Basically want to extend the System.Type with this functionality so what is the best way to write this function correctly:

    public static bool ImplementsInterface( this Type type, Type interfaceType )
    {
        foreach( Type implementedType in type.GetInterfaces() )
        {
            if( interfaceType.GetTypeInfo().IsGenericType )
            {
                if( implementedType.GetTypeInfo().IsGenericType == true &&
                     implementedType.GetGenericTypeDefinition() == interfaceType )
                {
                    return true;
                }
            }
            else
            {
                if( implementedType == interfaceType )
                    return true;
            }
        }

        return false;
    }

I feel there must be a more nice way than this :) Thank you!