Build a window application as a DLL library in Visual Studio 2019 C++

Question

I need help in solving a problem, as I simply do not have enough experience. I created a simple winodws in Visual Studio 2019 and it works well, but I need to compile it as a dll library so that a third-party application can call a function from this library and the window is drawn.

I don't plan any interaction with the application that called this function from the dll yet - I just want to show a window.

The actual code for the exe file is quite simple:

#include "MyForm.h"

#include <Windows.h>

using namespace windows2;


int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int) {

    Application::EnableVisualStyles();

    Application::SetCompatibleTextRenderingDefault(false);

    Application::Run(gcnew MyForm);

    return 0;
}

I tried to convert it to a dll file but when compiling I get errors

BOOL APIENTRY DllMain(HMODULE hModule,
    DWORD  ul_reason_for_call,
    LPVOID lpReserved
)
{
    Application::EnableVisualStyles();
    Application::SetCompatibleTextRenderingDefault(false);
    Application::Run(gcnew MyForm);
    
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}

Severity Code Description Project File Line Suppression State Warning C4747 Calling managed 'DllMain': Managed code may not be run under loader lock, including the DLL entrypoint and calls reached from the DLL entrypoint windows2 C:\VIsualC\windows2\windows2\MyForm.cpp 1

Can someone tell me how to compile this window into a dll?

The entire project in a zip archive for VS in its entirety

Answer 1

In Visual Studio, then change Project-> Properties-> Configuration Properties-> General-> Configuration Type from Application (.exe) to Dynamic Library (.dll) (Don't forget to choose the corresponding platform, your project is x64.)