Create Window and Swapchain with CsWin32

CreateWindowAndSwapChainCsWin32.cs

using System;
using System.Runtime.InteropServices;
using System.Runtime.Versioning;
using Microsoft.Win32.SafeHandles;
using Windows.Win32;
using Windows.Win32.Foundation;
using Windows.Win32.Graphics.Direct3D;
using Windows.Win32.Graphics.Direct3D11;
using Windows.Win32.Graphics.Dxgi;
using Windows.Win32.Graphics.Dxgi.Common;
using Windows.Win32.System.Com;
using Windows.Win32.UI.WindowsAndMessaging;

[assembly: SupportedOSPlatform("windows10.0.10240")]

namespace ConsoleApp5;

internal class Program
{
    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
    private delegate LRESULT WndProcDelegate(HWND hwnd, uint msg, WPARAM wp, LPARAM lp);
    private static readonly WndProcDelegate _wndProc = WndProc;

    static unsafe void Main()
    {
        ID3D11Device* device;
        PInvoke.D3D11CreateDevice(
            null,
            D3D_DRIVER_TYPE.D3D_DRIVER_TYPE_HARDWARE,
            HMODULE.Null,
            D3D11_CREATE_DEVICE_FLAG.D3D11_CREATE_DEVICE_DEBUG,
            null,
            0,
            7,
            &device,
            null,
            null).ThrowOnFailure();
        PInvoke.CreateDXGIFactory2(DXGI_CREATE_FACTORY_FLAGS.DXGI_CREATE_FACTORY_DEBUG, typeof(IDXGIFactory3).GUID, out var obj).ThrowOnFailure();
        var fac = (IDXGIFactory3*)obj;

        var clsName = "MyWindowClass";
        var cls = new WNDCLASSW
        {
            lpfnWndProc = (delegate* unmanaged[Stdcall]<HWND, uint, WPARAM, LPARAM, LRESULT>)Marshal.GetFunctionPointerForDelegate(_wndProc)
        };

        fixed (char* n = clsName)
        {
            cls.lpszClassName = n;
        }

        PInvoke.RegisterClass(cls);
        cls.hInstance = PInvoke.GetModuleHandle(new PCWSTR());
        PInvoke.RegisterClass(cls);
        var hwnd = PInvoke.CreateWindowEx(
            0,
            clsName,
            "test",
            WINDOW_STYLE.WS_OVERLAPPED,
            0,
            0,
            100, 100,
            HWND.Null,
            null,
            new SafeFileHandle(cls.hInstance.Value, false), // whatever handle
            null);

        IDXGISwapChain1* sw;
        var desc = new DXGI_SWAP_CHAIN_DESC1()
        {
            BufferCount = 2,
            Format = DXGI_FORMAT.DXGI_FORMAT_R8G8B8A8_UNORM,
            BufferUsage = DXGI_USAGE.DXGI_USAGE_RENDER_TARGET_OUTPUT,
            SwapEffect = DXGI_SWAP_EFFECT.DXGI_SWAP_EFFECT_FLIP_DISCARD,
            Scaling = DXGI_SCALING.DXGI_SCALING_NONE,
            Flags = DXGI_SWAP_CHAIN_FLAG.DXGI_SWAP_CHAIN_FLAG_FRAME_LATENCY_WAITABLE_OBJECT,
            SampleDesc = new DXGI_SAMPLE_DESC { Count = 1 },
        };

        fac->CreateSwapChainForHwnd((IUnknown*)device, hwnd, desc, null, null, &sw).ThrowOnFailure();
        sw->QueryInterface(typeof(IDXGISwapChain3).GUID, out var ppvObject).ThrowOnFailure();
        var sw3 = (IDXGISwapChain3*)ppvObject;

        var h = sw3->GetFrameLatencyWaitableObject();
        Console.WriteLine(h.Value);

        sw->Release();
        fac->Release();
        device->Release();
    }

    static LRESULT WndProc(HWND hwnd, uint msg, WPARAM wp, LPARAM lp)
    {
        return PInvoke.DefWindowProc(hwnd, msg, wp, lp);
    }
}

With NativeMethods.txt:

IDXGISwapChain3
IDXGIFactory3
CreateDXGIFactory2
D3D11CreateDevice
CreateWindowExW
RegisterClassW
GetModuleHandleW
DefWindowProcW