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Comment by xamluser | Hacker News Reader

You might want to look at the UWP version of XAML. It has really useful things like compiled bindings (x:Bind), calling functions as part of a binding with automatic change detection of the function params (x:Bind only), x:Phase for progressive enhancement during scrolling, StateTriggers, and Setters for visual states (consolidated VisualStateManager and Triggers).

Not to mention the interop with the amazing Windows.UI.Composition API's, which let you do expression animations, Direct2D effects, lighting, parallax, backdrop brushes (e.g., blur the content behind an element), etc.

WPF's version of XAML feels quite dated now.

Also, doing layout on the UI thread is a severe perf limitation that currently affects all versions of XAML. Consider having the UI framework just specify constraints and letting the compositor/render thread compute the absolute positions ;)

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Yeah UWP has a lot of good features but I always find when I go to it that it just lacks so many basics. It's like they kept building good stuff on top of Silverlight which stripped out a lot of useful stuff. Having said that I've not used it extensively (I had a good stab at Metro, but man that sucked) and ever since haven't gone back.

It's not x-plat either ;)

Obviously with Avalonia we have a long way to go (hence the Alpha) so we're getting the basics down first.

Layout on the UI thread is definitely a limitation too. I'd be interested to hear ideas as to how it could be done in a threaded manner.

UWP XAML has pretty much surpassed WPF with the latest SDK. There are some things missing, but the new features outweigh that and the performance is significantly better since it's all C++ and sits on top of DirectComposition instead of milcore. Many of the things that were removed (like FindAncestor bindings and DataContext inheritance) were done so for perf reasons or because they were refundant.

I'd use it as the basis for Avalonia instead of WPF. If only to have x:Bind instead of {Binding}, which thanks to function bindings removes a lot of ViewModel boilerplate.

I'm not on Win10 - are UWP apps still slow and clunky? Like they don't really act like normal windows? Still tablet-optimized or whatever? Last I checked on the W10 beta calc took several seconds to launch. (And had far less features, like no editable history.)

MS flubbed the launch and followup on Metro so hard (not to mention the shitware on the Store) it's really, really, turned me off from using or playing with it.

WinRT XAML is much faster than WPF ever was, it's just that they've started using it in very performance sensitive places where they never used any form of XAML before, like the calculator and start menu (the XAML calculator definitely doesn't take several seconds for me BTW, more like one second, but that's still too slow IMO), and it's still slower than the internal frameworks and bare Win32 calls they used to use. If they were WPF they'd be even slower.

In general, UWP apps that feel slow or somehow off are web apps. UWP XAML is really fast.

I'm not super familiar with x:Bind, but based on what you're describing, it sounds like something that could be done in WPF (or, presumably, something that copies its design), as a markup extension. Fpr example (note wpf:Lambda):

https://github.com/Microsoft/RTVS/blob/828b4e3919cbed507a4d0...

Obviously this is still more verbose, because it is a converter on a binding (although it could be shortened further by providing a custom Binding-derived class, I think).

do you know any good resources that provide insights on the differences between WPF and UWP?

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