UWP UI application in Rust

[DJankauskas]

Is it possible to create a uwp app with a ui with this library? If so can an example for that use case be added? If not what's preventing this: technical issues or something else?

[Boddlnagg]

It's currently not possible, because creating a UI requires inheritance (you have to define at least your own subclass of Application, if I understand things correctly in https://blog.magnusmontin.net/2017/10/29/minimal-uwp-app/), and inheritance is not yet supported in winrt-rust.

Since I also have never built a UWP UI App in any other language, I lack experience with this, which is why I haven't yet tackled this area in winrt-rust.

Furthermore, I expect that rustc itself also needs some support for generating actual UWP Apps (e.g. for App package manifests), which isn't there yet, or at least has never been tried. Everything I have tested so far is bascially traditional "Win32"-Apps using some UWP APIs (since most UWP APIs outside the Xaml namespace can actually be used from Win32-Apps).

[Boddlnagg]

Quick answer from my side: I don't know (because I've never used inheritance in UWP). Probably it's a rather large effort. Help appreciated!

[DJankauskas]

Could you offer some pointers on understanding how inheritance is implemented in cppwinrt? I've used that library before so I'd be willing to explore how its implementation works.

[CarePackage17]

Rustc doesn't need to do anything .appx related - packaging is done with separate tooling, though integration with cargo would be nice.

@DJankauskas, inheritance in C++ (and COM, which the Windows Runtime is built on) is implemented with vtables (pointers to virtual functions).
There's a lot more going on in cppwinrt under the covers, a lot of plumbing is hidden away from the developer.

That said, I'd also be interested in an effort like this. I think it would be pretty cool to have Rust running on HoloLens.

[Boddlnagg]

Related: rust-lang/rust#60260 (UWP support for Rust)

[rpjohnst]

Also related: https://docs.microsoft.com/en-us/windows/uwp/xaml-platform/xaml-host-controls

You can now (on new enough versions of Windows) use some amount of UWP UI outside of an appcontainer.