Template class is not exported from WinRT Component

Question

The following code attempts to create and export a template class from a WinRT component dll.  This code compiles fine, but the class is not visible in a C# Metro consumer application.  Why?

   template<typename T>
   public ref class TemplateClass sealed
   {
      private: T _item;
      public: TemplateClass(){_item = nullptr;}
      public: TemplateClass(T item)
      {
         _item = item
      }
      public: T Test()
      {
         return _item;
      }
   };

   public ref class NonTemplateClass sealed
   {
      private: int _value;
      public: NonTemplateClass() {}
      public: NonTemplateClass(int value)
      {
         _value = value;
      }
      public: int Test()
      {
         return _value;
      }
   };

Answer 1

Hello,

 

Thanks for your feedback, I will involve more experts to investigate it.

 

Best regards,

Jesse

---

Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 2

Were you able to involve enough experts to find a solution?

Answer 3

Public template classes are not allowed in C++/CX.

The code compiled due to a bug in RC. With the RTM compiler, you will get an error:

1>app.xaml.cpp(33): error C3401: 'Foo' : invalid assembly access specifier - only 'private' is allowed on class templates

Marian Luparu
Visual C++
 

Answer 4

I just finished watching a Build2011 video that explains how "Generics" are essentially Templates.  I suspect you'll feel right at home with Generics as they seem identical to templates.

http://channel9.msdn.com/Events/BUILD/BUILD2011/TOOL-532T  offset: 00:32:00 Generics

---

MCAD.NET C# - http://www.Global-webnet.com/Blog