The Rust for Windows crate does not currently support XAML, etc. That was yanked out for various reasons. But to get to the core of your issue, it sounds like you want to use Windows.Graphics.Capture APIs and are battling some dependencies.
I suggest taking a look at Rob's screenshot-rs crate; it demonstrates correct usage of Windows.Graphics.* APIs (https://github.com/robmikh/screenshot-rs) with Rust.