C++/CLI: Implementing IList and IList<T> (explicit implementation of a default indexer)
-
22-08-2019 - |
Question
I am trying to implement a C++/CLI class that implements both IList
and IList<T>
.
Since they have overlapping names, I have to implement one of them explicitly, and the natural choice should be IList.
The implicit implementation of the indexer is:
using namespace System::Collections::Generic;
generic<class InnerT> public ref class MyList : public System::Collections::IList, IList<InnerT> {
// ...
property InnerT default[int]{
virtual InnerT get(int index);
virtual void set(int index, InnerT item);
}
}
I am now trying to declare the default indexer for IList.
My guess would be something like this:
property Object^ System::Collections::IList::default[int]{
virtual Object^ System::Collections::IList::get(int index);
virtual void System::Collections::IList::set(int index, Object^ item);
}
but that just gives me
error C2061: syntax error : identifier 'default'
Any hints?
Solution
JaredPar's answer almost worked. Two things should be changed:
- The indexer-property needs a different name since "default" is already taken by the implicit implementation.
- The specification of the overriding needs to be done on the set- and get-methods, not on the property itself.
I.e.:
property Object^ IListItems[int]{
virtual Object^ get(int index) = System::Collections::IList::default::get;
virtual void set(int index, Object^ item) = System::Collections::IList::default::set;
}
OTHER TIPS
Haven't done a lot of interfaces in C++/CLI but this appears to be covered 8.8.10.1 of the C++/CLI spec. I believe the feature you're looking for is explicit overriding. In this you must specify the implemented member after the definition like so.
property Object^ default[int] = System::Collections::IList::default {... }
I compiled a class implementing IList<T>
explicitly written in C# and opened it with Reflector and disassembled to C++/CLI.
T System::Collections::Generic::IList<T>::get_Item(Int32 __gc* index)
{
//
}
void __gc* System::Collections::Generic::IList<T>::set_Item(Int32 __gc* index, T value)
{
//
}
But it doesn't compile: get_Item
, set_Item
is not a member of IList<T>
;