8 ms·

Avalonia Alpha 4 – A cross-platform .NET UI framework

95 points by grokys 10y ago

xamluser 10y ago
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 ;)
- grokys 10y ago
  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.
  - xamluser 10y ago
    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.
    - neppo 10y ago
      do you know any good resources that provide insights on the differences between WPF and UWP?
    - MichaelGG 10y ago
      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.
      - xamluser 10y ago
        In general, UWP apps that feel slow or somehow off are web apps. UWP XAML is really fast.
      - contextfree 10y ago
        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.
    - int_19h 10y ago
      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/828b4e3919cbed507a4d0f51b621b00a7fc8c25b/src/Package/Impl/DataInspect/VariableView.xaml#L91 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).
k__ 10y ago
What's the USP? How does it compare to Qt, Xamarin an Electron?
- grokys 10y ago
  It's based on the XAML family of frameworks so lookless controls are probably the biggest differentiator between the frameworks you mentioned. Qt is C++, I've not tried any .Net bindings for it so I can't really compare. Xamarin uses native controls, which just a different approach really. Electron is great but you're embedding chromium in an OS window which doesn't work for everyone.
jaybo_nomad 10y ago
Does anyone have a prediction when .NET Core will be extended to include UI? I find this lack is the most confounding aspect of MSFTs strategy. Is Xamarin really it?
- mattkrea 10y ago
  I'm pretty sure you'll be waiting a while. The GUI elements are tied very deep into core of Windows AFAIK.
  - bunderbunder 10y ago
    They are for WinForms and WinRT, but not so much for WPF. That one's closely related to Silverlight, which also runs on other platforms. I doubt WPF is going to make a big comeback, though.
    - pjmlp 10y ago
      WPF is still the way to go for many desktop enterprise apps. Thankfully there are still plenty of use cases not covered by web UIs.
- mythz 10y ago
  MSFT strategy is to develop a lightweight, cross-platform .NET runtime that can be hosted on Linux/Windows on Azure - that's where their ROI lies and where their .NET Core investments are focused. Their mobile/cloud approach is about using Xamarin to develop iOS/Android Apps that connect to backend Services hosted on Azure. Although they won't mind if you use Swift or Java to develop native iOS Apps or deploy on Linux - just as long as you host your backend Services on Azure. There's very little incentive for them to invest in making a cross-platform Desktop UI, most x-plat UI's suck and requires significant resources and offer little return given the most popular UI's are either Web/Mobile - which they've already got covered. I'd expect the most likely UI for .NET Core is to host a .NET Core runtime with a cross-platform web-based shell using something like Electron or CEF.
- pjmlp 10y ago
crudbug 10y ago
Does XAML provide react like component model with lifecycle hooks.
deleted 10y ago
[deleted]

95 points by grokys 10y ago

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 ;)

grokys 10y ago
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.
- xamluser 10y ago
  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.
  - neppo 10y ago
    do you know any good resources that provide insights on the differences between WPF and UWP?
  - MichaelGG 10y ago
    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.
    - xamluser 10y ago
      In general, UWP apps that feel slow or somehow off are web apps. UWP XAML is really fast.
    - contextfree 10y ago
      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.
  - int_19h 10y ago
    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/828b4e3919cbed507a4d0f51b621b00a7fc8c25b/src/Package/Impl/DataInspect/VariableView.xaml#L91 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).

k__ 10y ago

What's the USP? How does it compare to Qt, Xamarin an Electron?

grokys 10y ago
It's based on the XAML family of frameworks so lookless controls are probably the biggest differentiator between the frameworks you mentioned. Qt is C++, I've not tried any .Net bindings for it so I can't really compare. Xamarin uses native controls, which just a different approach really. Electron is great but you're embedding chromium in an OS window which doesn't work for everyone.

jaybo_nomad 10y ago

Does anyone have a prediction when .NET Core will be extended to include UI? I find this lack is the most confounding aspect of MSFTs strategy. Is Xamarin really it?

mattkrea 10y ago
I'm pretty sure you'll be waiting a while. The GUI elements are tied very deep into core of Windows AFAIK.
- bunderbunder 10y ago
  They are for WinForms and WinRT, but not so much for WPF. That one's closely related to Silverlight, which also runs on other platforms. I doubt WPF is going to make a big comeback, though.
  - pjmlp 10y ago
    WPF is still the way to go for many desktop enterprise apps. Thankfully there are still plenty of use cases not covered by web UIs.
mythz 10y ago
MSFT strategy is to develop a lightweight, cross-platform .NET runtime that can be hosted on Linux/Windows on Azure - that's where their ROI lies and where their .NET Core investments are focused. Their mobile/cloud approach is about using Xamarin to develop iOS/Android Apps that connect to backend Services hosted on Azure. Although they won't mind if you use Swift or Java to develop native iOS Apps or deploy on Linux - just as long as you host your backend Services on Azure. There's very little incentive for them to invest in making a cross-platform Desktop UI, most x-plat UI's suck and requires significant resources and offer little return given the most popular UI's are either Web/Mobile - which they've already got covered. I'd expect the most likely UI for .NET Core is to host a .NET Core runtime with a cross-platform web-based shell using something like Electron or CEF.
pjmlp 10y ago

crudbug 10y ago

Does XAML provide react like component model with lifecycle hooks.

deleted 10y ago

[deleted]