XAML Islands allows you use modern UWP XAML UI in Win32 apps. However, the .xaml sources will be compiled and bundled in a resource.pri file. You have to ship it with your executable.
Also according to the document from Microsoft, XAML part of your app is complied as a DLL, and it has a dependency of Microsoft.Toolkit.Win32.UI.SDK, which is another DLL. So finally you have to ship at least three other files with your exe file.
This project is based on this document.
Since Microsoft doesn't provide an API to load resource.pri from memory. It's done by hooking some system function. So I may not working in future version of Windows.
According to debugging, the resource.pri is loaded by MrmCoreR.dll. It first call GetFileAttributesExW to get information of resource.pri.
Then call GetDriveTypeW to get drive type of resource file.
Finally it call CreateFileW to open the file. If the drive type is fixed, it use MapViewOfFile to map the file to memory and read that memory. If the drive type is not fixed, it use ReadFile to read the file directly.
This program hook CreateFileW, and use CreatePipe to create an anonymous pipe, write content of resource.pri into the pipe, then return the read handle of the pipe.
Hook GetDriveTypeW and return DRIVE_REMOVABLE to force MrmCoreR.dll to use ReadFile.
Hook GetFileAttributesExW to return correct information of resource file.
Windows 11 brings a new UI. However it's required to add WinUI resources to your App.xaml file, like this:
<Application.Resources>
<XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
</Application.Resources>
And by doing so, you have to ship Microsoft.UI.Xaml.dll with your exe file. You can't use the one installed in system, until Windows 11.
Windows 11 added dynamic dependency API, which allow unpackaged apps to reference and to use framework packages such as WinUI 2.
This part of code is in winui2 branch. You can compare it with main branch to see differents.
Because of a bug of current Windows 11, the dynamic dependency API functions is not present in kernel32.dll, they are in kernelbase.dll or kernel.appcore.dll (This is forwards to kernelbase.dll). However the import library provided by Windows 11 SDK declares they are in kernel32.dll, which makes the program unable to start.
You have to load those functions manually using GetProcAddress, or link with OneCoreUAP_apiset.Lib, or create an import library that links to kernelbase.dll.
With Microsoft Dynamic Dependency code from WindowsAppSDK, now it's able to use WinUI 2 on Windows 10.
This part of code is in winui2-win10 branch.