Large amount of errors regarding "IServiceProvider"

Question

Strange issue...

This is using VisualStudio Community 2017 and is a C++CLI WinForms project.

BGStatsInterface.cpp

#include "BGStatsInterface.h"

using namespace System;
using namespace System::Windows::Forms;

[STAThreadAttribute]
void Main(array<String^>^ args) {
    Application::EnableVisualStyles();
    Application::SetCompatibleTextRenderingDefault(false);
    BattlegroundStats::BGStatsInterface form;
    Application::Run(%form);

}

BGStatsInterface.h

#pragma once
#include <windows.h>
#include "LuaReader.h"


namespace BattlegroundStats {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;
    using namespace System::IO;

    public ref class BGStatsInterface : public System::Windows::Forms::Form
    {
    public:
        BGStatsInterface(void)
        {
            InitializeComponent();
            this->MinimizeBox = false;
            this->MaximizeBox = false;
        }

        static System::Windows::Forms::TextBox^  textBoxLog;
        static System::Void addMsg(String^ text) {
            textBoxLog->AppendText(text + "\n");
        }

    protected:
        ~BGStatsInterface()
        {
            if (components)
            {
                delete components;
            }
        }

    private: LuaReader ^ reader = gcnew LuaReader();
    private: System::Windows::Forms::Button^  b1;

    private:
        System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code

        void InitializeComponent(void)
        {
            this->textBoxLog = (gcnew System::Windows::Forms::TextBox());
            this->b1 = (gcnew System::Windows::Forms::Button());
            this->SuspendLayout();
            // 
            // textBoxLog
            // 
            this->textBoxLog->BackColor = System::Drawing::SystemColors::ControlLightLight;
            this->textBoxLog->Cursor = System::Windows::Forms::Cursors::IBeam;
            this->textBoxLog->Font = (gcnew System::Drawing::Font(L"Microsoft Sans Serif", 6.75F, System::Drawing::FontStyle::Regular, System::Drawing::GraphicsUnit::Point,
                static_cast<System::Byte>(0)));
            this->textBoxLog->Location = System::Drawing::Point(10, 80);
            this->textBoxLog->Multiline = true;
            this->textBoxLog->Name = L"textBoxLog";
            this->textBoxLog->ReadOnly = true;
            this->textBoxLog->ScrollBars = System::Windows::Forms::ScrollBars::Vertical;
            this->textBoxLog->Size = System::Drawing::Size(280, 90);
            this->textBoxLog->TabIndex = 6;
            this->textBoxLog->TabStop = false;
            this->textBoxLog->GotFocus += gcnew System::EventHandler(this, &BGStatsInterface::textBoxLog_HideCaret);
            // 
            // b1
            // 
            this->b1->Location = System::Drawing::Point(100, 30);
            this->b1->Name = L"b1";
            this->b1->Size = System::Drawing::Size(75, 23);
            this->b1->TabIndex = 7;
            this->b1->Text = L"DoSomething";
            this->b1->UseVisualStyleBackColor = true;
            this->b1->Click += gcnew System::EventHandler(this, &BGStatsInterface::b1_Click);
            // 
            // BGStatsInterface
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(301, 411);
            this->Controls->Add(this->b1);
            this->Controls->Add(this->textBoxLog);
            this->FormBorderStyle = System::Windows::Forms::FormBorderStyle::FixedSingle;
            this->MaximumSize = System::Drawing::Size(317, 450);
            this->MinimumSize = System::Drawing::Size(317, 450);
            this->Name = L"BGStatsInterface";
            this->Text = L"Test";
            this->ResumeLayout(false);
            this->PerformLayout();
        }
#pragma endregion

        System::Void textBoxLog_HideCaret(System::Object^ sender, System::EventArgs^ e) {
            TextBox^ focus = safe_cast<TextBox^>(sender);
            HideCaret((HWND)focus->Handle.ToPointer());
        }

        System::Void b1_Click(System::Object^  sender, System::EventArgs^  e) {
            reader->DoSomething();
            addMsg("DoingSomethingA");
            System::Diagnostics::Debug::WriteLine("DoingSomethingA");
        }
    };
}

LuaReader.cpp

#include "LuaReader.h"
#include "BGStatsInterface.h" // PointA- This is where I'm having the issue.

using namespace System;

LuaReader::LuaReader(){}
System::Void LuaReader::DoSomething() {
    BattlegroundStats::BGStatsInterface::addMsg("DoingSomethingB");
    System::Diagnostics::Debug::WriteLine("DoingSomethingB");
}

LuaReader.h

#pragma once
#include "GameCollection.h" // PointB - Another issue here.

ref class LuaReader
{

public:
    LuaReader();
    GameCollection^ gameData = gcnew GameCollection();
    System::String^ _fileName;
    System::Void DoSomething();
};

#endif

GameCollection.cpp

#include "GameCollection.h"
GameCollection::GameCollection(){}

GameCollection.h

#pragma once
using namespace System;

ref class GameCollection
{
public:
    GameCollection();
};

The Problem:

In LuaReader.cpp If I include BGStatsInterface.h (needed so it can access the addMsg method), noted by PointA, it wont compile and will generate the errors listed below.

However, if I remove the GameCollection.h include from LuaReader.h (needed so I can create the GameCollection object), noted at PointB, it has no issues with BGStatsInterface.h included in the LuaReader.cpp file and everything compiles/runs without issues.

I don't know what to do... Why does it only work if I don't create the GameCollection object in LuaReader.h?

What have I done wrong?

Errors:

Severity    Code    Description Project File    Line    Suppression State
Error (active)  E1986   an ordinary pointer to a C++/CLI ref class or interface class is not allowed    BattlegroundStats   c:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\um\servprov.h   91  
Error (active)  E0266   "IServiceProvider" is ambiguous BattlegroundStats   c:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\um\servprov.h   115 
Error (active)  E0266   "IServiceProvider" is ambiguous BattlegroundStats   c:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\um\servprov.h   239 
Error (active)  E0266   "IServiceProvider" is ambiguous BattlegroundStats   c:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\um\servprov.h   249 
Error (active)  E0266   "IServiceProvider" is ambiguous BattlegroundStats   c:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\um\urlmon.h 6867    
Error (active)  E0266   "IServiceProvider" is ambiguous BattlegroundStats   c:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\um\urlmon.h 6869        
Error   C3699   '*': cannot use this indirection on type 'IServiceProvider' BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\servprov.h   91  
Error   C2371   'IServiceProvider': redefinition; different basic types BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\servprov.h   98  
Error   C2872   'IServiceProvider': ambiguous symbol    BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\servprov.h   115 
Error   C2872   'IServiceProvider': ambiguous symbol    BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\servprov.h   239 
Error   C2872   'IServiceProvider': ambiguous symbol    BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\servprov.h   249 
Error   C2872   'IServiceProvider': ambiguous symbol    BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\urlmon.h 6867    
Error   C2872   'IServiceProvider': ambiguous symbol    BattlegroundStats   c:\program files (x86)\windows kits\10\include\10.0.16299.0\um\urlmon.h 6869    

Answer 1

This happens when using #include Windows.h as it defines ::IServiceProvider while the framework has System::IServiceProvider, then when there's a using namespace System in scope somewhere it becomes ambiguous.

Solution is to simply put the delcarations in your own namespace.