C++/CLI does support interface-based constraints on generics. An interface constraint basically allows you to specify that a given generic parameter type must implement a certain interface (or derive from a given base class), thus allowing you to call any methods (or access any properties) that are part of said interface.

In C++/CLI, you specify an interface constraint just after the closing > specifying the generic arguments, using the "where" keyword followed by the generic argument, a colon, and the interface it should implement. Here's an example that requires that argument T implements IEnumerable<V>:

#using <mscorlib.dll>

using namespace System;
using namespace System::Collections::Generic;


generic <typename T, typename V>
   where T : IEnumerable<V>
ref class IWillEnumerateYou
{
public:
   void DoIt(T t)
   {
      for each ( V v in t )
      {
         Console::WriteLine(v);
      }
   }
};

int main()
{
   List<String^>^ stringList = gcnew List<String^>();
   stringList->Add("String 1");
   stringList->Add("String 2");
   stringList->Add("String 3");
   IWillEnumerateYou<List<String^>^, String^>^ en 
      = gcnew IWillEnumerateYou<List<String^>^, String^>();
   
   en->DoIt(stringList);
      
}