C++/WinRT how to include an enum class in .h file for IDL file

Question

Here is my .h file.

#pragma once

#include "pch.h"
#include "TCP_Page.g.h"

using namespace winrt;
using namespace std;
using namespace Windows::UI;
using namespace Windows::UI::Core;
using namespace Windows::UI::ViewManagement;
using namespace Windows::UI::Xaml;
using namespace Windows::UI::Xaml::Interop;
using namespace Windows::UI::Xaml::Controls;
using namespace Windows::UI::Xaml::Navigation;
using namespace Windows::UI::Xaml::Media::Animation;
using namespace Windows::Foundation;
using namespace Windows::Networking::Connectivity;
using namespace Windows::Storage::Streams;

enum class NotifyType
{
    NoNotifyTypeMessage,
    StatusMessage,
    ErrorMessage
};

namespace winrt::GUI_Test::implementation
{
    struct TCP_Page : TCP_PageT<TCP_Page>
    {
        TCP_Page();
        void UpdateStatus(hstring strMessage, NotifyType type);
        void NotifyUser(hstring strMessage, NotifyType type);
        void NotifyUserFromAsyncThread(hstring strMessage, NotifyType type);
        ...
    };
}

namespace winrt::GUI_Test::factory_implementation
{
    struct TCP_Page : TCP_PageT<TCP_Page, implementation::TCP_Page>
    {
    };
}

Here is my IDL file.

namespace GUI_Test
{
    [default_interface]
    runtimeclass TCP_Page : Windows.UI.Xaml.Controls.Page
    {
        TCP_Page();
        void UpdateStatus(String strMessage, NotifyType type);
        void NotifyUser(String strMessage, NotifyType type);
        void NotifyUserFromAsyncThread(String strMessage, NotifyType type);
    }
}

Here is the error I get.

Error MIDL2011 [msg]unresolved type declaration [context]: GUI_Test.NotifyType [ Parameter 'type' of Procedure 'UpdateStatus'( RuntimeClass 'GUI_Test.TCP_Page' ) ]

I have never dealt with an IDL file before. Because NotifyType is an enum and is declared in the .h file, the IDL file can't resolve its type. I just don't know exactly what to do to solve the issue. Importing the .h file did not seem to fix it unless I put it on the wrong line which was the line before TCP_Page(). Since I made the enum a class, I figure that might be the problem. I suppose I could just add it to the IDL file, but then I will have 2 places that I need to maintain the code. Not a good solution.

This is probably easy to fix, I just have no clue on how to do it. Thanks.

Answer 1

Maybe try dividing into two files:

// first.idl

namespace GUI_Test
{
   enum NotifyType
   {
      NoNotifyTypeMessage,
      StatusMessage,
      ErrorMessage
   };
}


// second.idl

import "first.idl";

namespace GUI_Test
{
   [default_interface]
   runtimeclass TCP_Page : Windows.UI.Xaml.Controls.Page
   {
      TCP_Page();
      void UpdateStatus(String strMessage, NotifyType type);
      void NotifyUser(String strMessage, NotifyType type);
      void NotifyUserFromAsyncThread(String strMessage, NotifyType type);
   }
}

Remove the enum from .h file and insert #include "first.idl". You can also rename first.idl to first.h.

It seems that 'enum class' is not supported.