DEV Community: Avalonia UI

WPF App Modernisation: A Pragmatic Approach

Mike James — Fri, 13 Oct 2023 08:37:55 +0000

In the world of desktop application development, continuity and stability often trump the allure of new frameworks. Notably, 58% of professional desktop developers stick with the familiar, avoiding radical changes to their applications. The predominant drive is maintaining or modernising applications within the familiar confines of their existing UI technologies. This preference is not without merit; developers find comfort in the known, and a lower developmental cost comes with familiarity. Rewriting an application is a significant financial and operational risk.

Cross-Platform UI Toolkits

That's not to say some teams aren't seriously considering their modernisation strategy. While WPF is stable and proven, it is limited to Windows at a time when more and more applications need to run on various operating systems and form factors. Before Avalonia XPF, WPF developers had limited options. One option would be to migrate to a cross-platform UI toolkit, such as Avalonia, Qt or Flutter, with the best-case scenario enabling some code reuse and the worst case requiring a complete application rewrite.

Web

The alternative to a cross-platform UI toolkit has been embracing Web technologies, whether Electron or moving to the cloud. It's hard to ignore the allure of web technology's ease of deployment, albeit at the potential expense of performance and productivity.

Why modernise

With so many mission-critical WPF applications in active development, the discussion of modernisation is buzzing. Why the discourse on modernisation, you ask? The answer is twofold: new platforms equate to an expanded target market and a resilient, future-proof application portfolio. The pathway to modernisation, however, is a strategic decision. Rewriting is an expensive endeavour, irrespective of the technology chosen. The crossroads broadly split into native cross-platform (embodied by Flutter, QT, Avalonia, etc...) or the web. Amongst the native cross-platform contenders, Avalonia emerges as the frontrunner in facilitating code reuse, a significant cost and time efficiency advantage. That isn't to say that Avalonia (our open-source, cross-platform UI toolkit) doesn't require some changes to your WPF app. It's WPF-inspired but not binary-compatible.

Avalonia XPF

If you need WPF binary compatibility, then Avalonia XPF has emerged as a solution to modernisation. It offers a path to new platforms without necessitating a seismic shift and rewriting existing applications. We typically see customers running their complex WPF application on new platforms within only a few hours of receiving a trial license! The attraction towards Avalonia XPF stems from a pragmatic standpoint; it's a fast and affordable conduit to broader market reach without the enormous risk of rewriting applications from scratch in a different technology.

Avalonia XPF shines distinctly, enabling full reuse of existing WPF code and 3rd party controls while providing performance improvements and new platforms. It's a proposition of extending the life and reach of your applications without a daunting overhaul.

There isn't a one-size-fits-all answer to app modernisation. It's a journey tailored to individual applications and a team's long-term vision. Engaging in a dialogue on modernisation, understanding the nuances and making informed decisions is the essence of staying ahead. We at Avalonia are at the helm to discuss, advise, and help you navigate the modernisation maze.

Next Steps

If you'd like to test your WPF applications on macOS or Linux, then sign up for a 30-day trial of Avalonia XPF.

Remember to download our XPF Sample app, FamilyShow. The classic WPF sample app is now available on macOS and Linux!

Introducing Avalonia XPF Trials and the Startup License

Mike James — Thu, 27 Jul 2023 11:00:09 +0000

At Avalonia, we embarked on the ambition project of Avalonia XPF with the aim of extending the reach of Windows Presentation Foundation (WPF) to a broader range of platforms. Today, as we witness numerous companies finding success with Avalonia XPF, we are proud of the progress we’ve made. The fruits of our labor are visible, and we’re thrilled to announce that we’re being XPF Trials and added a license specifically targeting small businesses.

Avalonia XPF Trials

After rigorous testing and refinement over many months with a select group of companies, we are now ready to extend Avalonia XPF trials to the broader community. Avalonia XPF has seen exponential improvements since the start of the year. We are now proudly supporting a significant proportion of major WPF control vendors. Collaborations with esteemed vendors like Actipro and SciChart are enabling us to ensure that controls function seamlessly across all supported platforms.

This exciting expansion of our testing phase is organized into four straightforward steps to ensure a seamless onboarding experience.

Step 1:
Users interested in exploring the potential of Avalonia XPF can apply for a trial through our website.

Step 2:
Our team will set up a short initial call to verify the compatibility of the user's app, discuss timelines, and understand specific requirements. This step allows us to personalize your trial experience.

Step 3:
Once we've established the app’s suitability and your readiness, we help set you up with the Avalonia XPF trial. Our dedicated team is on standby to assist should any issues arise while using Avalonia XPF.

Step 4:
After a successful trial, users can purchase a license to officially bring their WPF application to macOS and Linux, opening up their products to a significantly wider user base.

Startup License

The launch of Avalonia XPF trials signifies a new phase in our journey. But we're not stopping there. We've always aimed to make Avalonia's robust solutions accessible to a diverse range of developers and businesses, which is why we are thrilled to introduce the new Startup license.

Our initial vision for Avalonia XPF was to offer large enterprises a way to conserve valuable resources while extending their application's reach. We wanted to help companies save months, or even years, of work rewriting applications. To our delight, we found that the appeal of Avalonia XPF extended beyond large corporations. Many smaller companies have also expressed a keen interest in our technology. To accommodate these smaller companies and startups, we're offering an Startup license.

With significantly reduced costs, the Startup license is designed for companies with no more than five employees and annual revenues not exceeding 1 million USD. This license, while highly affordable, includes up to ten support tickets per year. We are confident that the Startup license will enable many more businesses to experience the transformative benefits of Avalonia XPF.

With Avalonia XPF and the introduction of the Startup license, we're not just expanding platforms and licensing options; we're expanding horizons, possibilities, and opportunities. We believe that with the right tools, developers and companies, regardless of their size, can build upon their existing WPF investments and increase their reach.

If you have a WPF application and are interested in exploring what Avalonia XPF can do for you, we would love to hear from you. Reach out to us, and let's embark on this exciting journey together.

To the future of WPF, we say: the future is here, the future is Avalonia XPF.

Avalonia for Visual Studio Code (Early Access)

Mike James — Thu, 27 Jul 2023 07:09:15 +0000

Two weeks ago we showed a sneak peak of Avalonia for Visual Studio Code. The extension will significantly enhance the Avalonia development experience in Visual Studio Code. It features our XAML code completion and integrated XAML previewer, making it easier than ever to build beautiful Avalonia apps.

Today, we are excited to invite you, the sponsors and the members of OpenCollective to try the (extremely) early build of the extension!

Please sign up for the early access here, we will start sending out instructions from the 27th of July.

What’s in the extension?

The extension aims to bring the most common workflows for Avalonia developers. However, the preview will enable the two most common scenarios to kick off the support for VSCode

Integrated XAML Previewer

The Avalonia XAML Previewer is a powerful tool that allows you to visualise XAML code in real-time. It enables you to efficiently design and fine-tune user interfaces, helping to identify potential issues and visualise the impact of changes instantly.

XAML Code completion

The Avalonia XAML in the VS Code is powered by the same code completion engine available for Visual Studio on Windows.

Rich syntax highlighter and contextual code complete will make it lot easier to read and write XAML files

Feedback

Please share your suggestions, feature requests and report issues for the extension through VS Code’s Help > Report Issue dialog

You can follow all the suggestions and issues the extension here.

Welcome to the New Era of App Development: Introducing Avalonia v11

Mike James — Wed, 05 Jul 2023 10:26:52 +0000

Today, we are thrilled to announce the release of Avalonia 11.0!

After nearly a year in preview and countless thousands of hours of dedication, it is time to unleash a game-changer in cross-platform application development. Avalonia v11 embodies a huge leap forward in our goal to provide developers with an efficient, feature-rich, and seamless experience to create exceptional UIs across all major platforms.

What makes Avalonia v11 a milestone in our journey? Here's a peek into the wealth of features we have packed into this revolutionary version:

Broadened Horizons with New Platforms

The broadened platform support is one of the most significant updates in v11. With this release, we've included iOS, Android, and WebAssembly support, taking our cross-platform capabilities to new horizons.

Looking to the future, we’ve also previewed support for Apple's visionOS and seen our incredible community work to enable Avalonia UI on Samsung's TizenOS! Our unique architecture enables us to add new platforms with ease, which we wrote about last year.

New Composition Renderer

Our new composition renderer is a significant advancement in visual capability and performance. At its core, the composition renderer brings new animation possibilities to the table. With support for implicit animations, connected animations and render thread animations, the visual dynamism of your application can reach new heights. These features allow for smooth, high-performance animations that can enrich your user interfaces and provide engaging user experiences.

Beyond the animation enhancements, the composition renderer provides substantial performance improvements. It’s designed to be highly efficient, reducing memory pressure and enabling high frame rates even on low-powered embedded devices. A testament to Avalonia's efficiency is its widespread use in embedded systems. Our architecture enables delivering a seamless user experience, even when operating on 20-year-old embedded CPUs. This level of performance optimization is rare, demonstrating Avalonia's ability to adapt to diverse hardware configurations while maintaining smooth, responsive applications.

Advanced Text Rendering and Layout

Avalonia v11 ushers in a new era of text rendering capabilities, significantly enhancing control and flexibility over the visual elements in your UI. We’ve introduced rich text rendering that supports inline elements. This feature allows for dramatic variations in a single TextBlock, from changing font styles to adding hyperlinks, or even embedding controls - something that wasn’t previously achievable.

These improvements and capabilities set the foundation for full rich text editing, a feature we’re excited to explore in the upcoming versions of Avalonia.

IME Support

Our commitment to global reach and inclusivity has led to the introduction of Input Method Editor (IME) support in v11. This vital feature assists users in entering characters and symbols not found on their input devices. IME support also enables seamless integration with on-screen keyboards on mobile and web platforms. This means that Avalonia apps now play nicely with features such as auto-completions and other OS provided text features. As a result, Avalonia apps are become even more user-friendly and adaptable to a range of input methods.

Accessibility Support

We believe that technology should be inclusive and accessible to all. Therefore, we're excited to introduce our new accessibility support, which ensures that Avalonia applications can be used and enjoyed by everyone, including those with disabilities.

We've laid the groundwork for full accessibility support, implementing critical features that make apps more accessible to users with visual, motor, or cognitive disabilities. These enhancements comply with industry standards and guidelines, making Avalonia a more attractive choice for developers concerned with building accessible software.

We've made strides in keyboard navigation, screen reader support, and high-contrast themes. And while we're proud of our progress, we consider this to be just the beginning. We're committed to continuously improving the accessibility of Avalonia, making it easier for everyone to use the applications built with our framework.

Automated Testing

We’ve overhauled our automated testing capabilities to ensure you can develop robust and reliable applications with ease. This release introduces support for automated testing that extends beyond the Avalonia test environment to include traditional testing frameworks like Appium. With v11, you can take advantage of the testing tools you’re already familiar with to ensure your application runs flawlessly across platforms.

But the enhancements to our testing capabilities go even further. With the introduction of a ‘Headless’ mode, you can run your entire application and execute tests on it at incredibly high speed. This headless mode streamlines the testing process, enabling you to validate functionality and detect bugs more efficiently than ever before. This is a monumental leap forward in our testing capabilities, and we believe it will dramatically improve your development workflow.

Control Themes

One of the notable enhancements in v11 is the significant improvements made to our control themes. While we've always prided ourselves on the customizability offered by Avalonia, in this version, we've taken it a step further to provide developers with even more flexibility and control over the look and feel of their applications.

Control themes in v11 have been restructured for easier customization, which is particularly beneficial if you have a precise, consistent visual identity you'd like to maintain across your applications. This ease of customization also increases efficiency, enabling you to achieve the desired aesthetic with less time and effort.

Additionally, we've improved our support for theme switching, allowing your users to switch between light and dark modes or other custom themes you provide seamlessly and dynamically.

AOT & Trimming

We're excited to announce that v11 fully supports Ahead-of-Time (AOT) compilation and trimming, resolving issues from previous versions. The updated trimming functionality eliminates unused code during the publishing process, dramatically reducing application sizes. With v11, developers can now experience ~60% smaller application sizes, providing faster downloads, quicker startup times, and less end-user storage used.

Revamped Developer Documentation

Your feedback has been invaluable, and we’ve heard you loud and clear about improving our documentation! We’re thrilled to reveal that we’ve transitioned our documentation from GitBook to a new custom platform that aligns more precisely with our evolving needs.

This significant step forward offers us enormous flexibility for future enhancements. The goal is to continually adopt and refine the documentation to better serve our expanding community.

We’ve also worked on creating quick-guides, which are focused example applications that demonstrate specific functionalities.

We hope to see more participation from the community to help us improve documentation. This doesn’t necessarily mean writing documentation yourself - although that would be welcome. Equally important is sharing your experiences. Tell us about the areas where you encountered hurdles, or where our current documentation fell short in supporting your journey. This kind of feedback is immensely valuable and helps us understand where to focus our improvement efforts. Every contribution, whether big or small, goes a long way in refining Avalonia into an even more developer-friendly framework.

Template Studio

We’ve released our first version of Template Studio for Avalonia - a streamlined solution designed to accelerate the creation of new Avalonia apps using an intuitive, wizard-based UI.

Getting started with Template Studio for Avalonia is a breeze. Simply install the extension and select the Template Studio project template when creating a new project in Visual Studio.

Ecosystem Growth

We've had the privilege of working closely with a range of pro-control vendors who have been developing specifically for Avalonia.

This marks an important milestone in Avalonia's journey as it signals a shift in the broader ecosystem - attracting commercial interest from vendors who have previously dedicated their efforts to supporting WPF, Xamarin and other Microsoft UI toolkits.

We’ve examined various .NET-based cross-platform UI frameworks for our next set of UI controls, but none of them capture the magic of WPF in the way that Avalonia does. Avalonia has a very strong community, offers pixel-perfect rendering on a multitude of platforms, is easy to customize, and frankly is a joy to work with.
Bill Henning, President, Actipro Software

It's exciting and humbling to observe this growth and be part of the vibrant community that is driving it. We're immensely grateful for the collaboration of these vendors and their belief in Avalonia's potential. As we move forward, we're enthusiastic about future collaborations and the continuing growth of Avalonia's ecosystem.

Thank you!

Avalonia has always been a labour of love, a community-driven project open to all. Over the past decade, more than 300 contributors worldwide have shaped Avalonia into what it is today. Avalonia v11 is not just a new version; it embodies our vibrant community's collective hard work and ambition to create the best cross-platform UI framework.

We invite you to join us on this exciting journey and help shape the next decade of Avalonia and the future of cross-platform .NET app development.

Getting Started

Ready to dive into Avalonia v11 and explore all the amazing new features? Head over to our Get Started guide to begin building with Avalonia.

If you’re already developing with Avalonia and want to upgrade to v11 then check out our upgrade guide.

First Release Candidate of Avalonia UI v11 Now Available!

Mike James — Thu, 01 Jun 2023 05:10:03 +0000

We're excited to announce that the first Release Candidate (RC) of Avalonia UI v11 is now available for you to try out!

This RC marks a significant milestone for us as it stabilises the API. It's been a journey of intense work, learning, and collaboration. And now, we can confidently say that we're closer than ever to the final release of v11

Now is the perfect time for you and your teams to test drive v11. As we progress, the only changes we're looking at are bug fixes. We believe this makes the RC a safe and exciting option to explore, especially if you're considering the upcoming production releases.

With a keen focus on maintainability, Avalonia UI v11 carries the most substantial changes in our API to date, setting the project up for a thriving future. We've poured considerable thought, time, and resources to ensure these changes pave the way for a more robust and reliable Avalonia UI. While this release represents our most substantial set of breaking changes, we expect future major releases will see significantly fewer breaking API changes.

As part of these breaking API changes, some previously public classes are now marked as 'Internal'. This change has been done to safeguard the integrity of applications by allowing us to modify implementations without introducing future breaking changes. While we've taken every measure to ensure a smooth transition, we acknowledge that you might encounter scenarios where a critical class is no longer visible. If you encounter such instances, we strongly encourage you to contact us. We're open to a dialogue about changing certain classes back to public visibility based on your valuable feedback.

We encourage everyone to try out the RC, provide your feedback, and help us make Avalonia UI v11 the best. We sincerely thank all our users, contributors, and the entire Avalonia community for your ongoing support.

Head over to nuget to get started. Let's build the future of cross-platform .NET UI technology together!

Happy coding!

Avalonia UI and MAUI - Something for everyone

Mike James — Wed, 29 Mar 2023 11:40:11 +0000

In the world of cross-platform .NET development, two popular frameworks have emerged as strong contenders: Avalonia UI and .NET MAUI (Multi-platform App UI). Both are powerful tools designed to solve different problems, making it essential to understand their key differences to make an informed choice for your project.

This blog post will delve into the primary distinction between these two technologies and the benefits of each approach.

Let's start with a brief overview of both Avalonia UI and MAUI.

Avalonia UI

Avalonia UI is an open-source, cross-platform UI framework that allows developers to create beautiful, responsive applications using a single codebase for multiple platforms, including Windows, macOS, Linux (desktop and embedded), WebAssembly and even mobile platforms. Avalonia UI leverages XAML for creating the UI, making it familiar to those with experience in WPF, UWP, WinUI or Xamarin.Forms.

While Avalonia UI is free and OSS, it is backed by a small, independent company formed by the core team responsible for the development of Avalonia UI. We offer development services, support agreements and recently announced our first product, Avalonia XPF. The goal of the company is to generate revenue to enable the core team to work on Avalonia UI full-time and to better serve enterprises building apps with Avalonia.

MAUI

MAUI (Multi-platform App UI) is an evolution of Xamarin.Forms. It's an open-source, cross-platform framework for building native UIs for iOS, Android, macOS, and Windows. MAUI simplifies creating apps with native user interfaces by enabling developers to develop in a single project. It uses the native UI toolkit of each platform, which allows developers to leverage platform-specific capabilities and build applications that feel native to each platform.

Developed by Microsoft, it has a large and dedicated community of users to lean on for support.

Now that we have a basic understanding of Avalonia UI and MAUI, let's dive deeper into their differences.

UI Drawing

Native vs Custom Rendering:

The primary difference between Avalonia UI and MAUI lies in how they draw the user interface. Avalonia UI employs a custom drawing engine powered by Skia (like Flutter), while MAUI uses native UI toolkits for each platform.

Let's explore these approaches in more detail.

MAUI

MAUI uses the native UI toolkit of each platform, resulting in an application that feels native to the platform it's running on. This means that a MAUI app on Android will use the native Android UI toolkit, while on iOS, it will use UIKit. This approach ensures that your application will have a look and feel that users expect on their devices. This approach offers several benefits:

Performance: By utilising native UI toolkits, MAUI can offer good performance, especially on mobile devices. It should be noted that on some platforms, objects will exist in both the .NET memory space and the platform UI toolkits memory. This can have a noticeable effect on performance compared to an app developed purely with the native technology. For example, on Android you will have two Garbage Collectors, one for the ART Runtime and one for the .NET runtime.

Platform-Specific Animations and Transitions: MAUI allows developers to harness platform-specific animations and transitions, giving applications a polished and native feel. By utilising the animations provided by the native UI toolkits, developers can create applications that are consistent with the design language of each platform and provide a familiar user experience.

Rapid Adoption of New Platform Features: As new features and UI components are introduced in native platforms, MAUI applications can quickly adopt these updates, ensuring that applications stay up-to-date with the latest design trends and platform improvements. This helps maintain a modern and consistent user experience while also reducing the time and effort needed to implement new features manually.

Avalonia UI

Unlike MAUI, Avalonia UI uses a custom rendering engine that draws UI elements consistently across all platforms. This means that your application will have the same appearance and behaviour regardless of the platform it's running on. Avalonia UI's custom rendering approach allows for greater control over the UI design and a consistent user experience across different platforms. This approach comes with its own set of benefits:

Consistency: Applications built with Avalonia UI have a consistent look and feel across platforms, which can be valuable for branding and user experience.

Flexibility: The custom drawing engine gives developers more control over their application's appearance and behaviour. They can create custom UI elements and styles that might not be possible or would require more effort using native UI toolkits.

Simplified Maintenance: Using a custom drawing engine means the UI code is the same across all platforms, simplifying maintenance and updates. Developers only need to change the shared codebase, reducing the time and effort required to maintain the application across multiple platforms.

Independent Evolution: Avalonia UI's custom drawing engine allows the framework to evolve independently of the native platforms it targets. This means that improvements, bug fixes, and new features can be implemented faster without having to wait for native platforms to catch up or maintain compatibility. As a result, Avalonia UI applications can benefit from continuous innovation and stay ahead of the curve in terms of UI and UX advancements.

Platform Support

While both technologies are both versatile and powerful UI frameworks, their platform support differs in some key areas.

Windows
MAUI provides support for Windows 10 and 11, depending on WinUI3, while Avalonia UI can target Windows 7 and higher.

macOS
As MAUI relies on Mac Catalyst, it supports macOS 10.15 (Catalina) and newer. Avalonia, on the other hand, supports macOS 10.13 (High Sierra) and higher.

Linux
At this time, MAUI doesn’t have any official support for Linux, though a community effort exists to enable MAUI to run on desktop Linux. Avalonia UI supports both desktop and embedded distributions of Linux, requiring no desktop environment to be installed. Officially supported distributions include Debian 9, Ubuntu 16.04 and Fedora 30 and higher.

iOS
MAUI supports iOS 11 and higher, while Avalonia UI supports iOS 13.

Android
MAUI supports Android 7.0 (API 24) and higher, while Avalonia UI supports Android 5 (API 21)

WebAssembly
It was recently announced that MAUI could be getting Web support after .NET 8, but at this time, there are no options to deploy your MAUI applications to the web. Avalonia UI supports WebAssembly today and has a fully interactive playground for exploring Avalonia UI on the web.

Solving Problems Differently

While both Avalonia UI and MAUI are powerful frameworks for cross-platform development, they are designed to address different concerns:

Avalonia UI is an excellent choice for developers who prioritise consistent branding and a uniform user experience across platforms. Its custom drawing engine provides flexibility in designing custom UI components and styles, making it perfect for creating unique and visually rich applications. Avalonia UI excels on desktop focused applications, with mobile and WebAssembly being new additions to the platform.

On the other hand, MAUI is the go-to choice for developers who need their applications to adhere to platform-specific design guidelines and provide a native look and feel. Its use of native UI toolkits ensures fantastic performance on various devices, and direct access to platform-specific APIs allows for seamless integration of native functionality. MAUI is a great choice for developing mobile centric applications, where desktop is a secondary or lower priority.

Conclusion

Avalonia UI and MAUI are both outstanding options for cross-platform development, each offering unique benefits depending on your project's requirements. The strength of the .NET ecosystem lies in its ability to provide developers with an array of options to choose from, ensuring they can select the most suitable approach for their specific project. The beauty of .NET is that a well architected application can reuse a huge amount of code, regardless of the UI framework used.

If you want to learn more about Avalonia UI and how it can help you develop visually stunning, high-performance applications for Windows, macOS, Linux, Android, iOS and WebAssembly then check out our getting started.

Turning it up to 11!

Dan Walmsley — Fri, 19 Aug 2022 15:01:00 +0000

For the last 2 years the team has been working hard to bring the next generation of Avalonia.

This has focused on platforms, features and performance.

We are pleased to announce the release of 11.0 Preview 1 today. It is available immediately on NuGet.

So what's new?

Platforms

We have made huge strides forward to bring Avalonia to Android, iOS and Embedded platforms.

Until now Avalonia had been dominant on the desktop. However many users wish to reuse their UI code on mobile and in the browser.

In this preview we have almost production ready solutions for iOS, Android and browser.

We have also had a huge push on support for embedded platforms, like Raspberry Pi, Torizen and more. Avalonia is light weight and able to run without a desktop environment.

Avalonia is now highly optimized for low power embedded platforms. It is able to boot extremely quickly and maintain high framerates.

See these products from some of our customers that are using Avalonia in embedded industrial products.

New Features

New Visual Layer (Composition Renderer)

Extremely efficient renderer with no memory pressure allowing high frame rates even on low power embedded devices. You can achieve 240fps without breaking a sweat.

New rendering capabilities are also enabled. We shall go into this more in a future post.

Full Featured Text Rendering and Layout

Text rendering and layout is harder than most realize. Our team has been working on this for several years now. Avalonia now has full unicode support and is able to layout and render text from any language, including right to left.

We also now have full featured support for rich text and inlines. We have the full TextFormatter API from WPF implemented which allows controls and applications that rely on rich text formatting to be ported from WPF.

This is a huge advance and proves that Avalonia is ready for the world, your application can now be used by people in any culture and language.

Avalonia now supports IME (input method editor) on all platforms, this means that languages i.e. CJK (Chinese, Japanese, Korean, etc) work as expected.

Accessibility

Accessibility is extremely important to us. We need to ensure that anyone can use the applications built on Avalonia.

We now have full support for accessibility on Window and MacOS. You do not have to make any changes to your application to enable this, it will simply just work. We have properties to customize accessibility names of components.

In future this support will be available also on Linux, Mobile and Browser.

Accessibility also enables new testing scenarios which leads us to….

Automated Testing

Automation or Automated testing is now possible. You can simply use Appium or other automated testing frameworks for desktop.

This means you can have a test that runs your application, interacts with it, and checks for the correct behavior.

This is traditionally how many applications are tested.

It is worth noting that Avalonia is a fully mockable platform. This means that you can actually test the same functionality inside unit tests with mocked controls and views.

We have had reports from customers stating that “migrating our tests from automated tests to mocked unit tests allowed us to run thousands of tests in just 3 seconds instead of several hours.”.

Having both mocked and automated tests gives developers the best opportunity to ensure the stability of their applications in production.

Control Themes

We have overhauled our styling system and added a new feature called Control Themes. This means that all the styles required for a control can be grouped together, and that you can apply different themes to specific parts of your application.

It also allows you to instantly switch between for example light and dark mode, which in the previous version could take a bit of time to process.

Control themes are also allowed to inherit styles.. Similar to WPFs “based on” styling mechanism.

Performance

There has been a huge focus on performance. Just upgrading to 11.0 will give your application a boost.

Themes, Styles and Resources are lazily loaded on demand. This means that your application will load much faster, without having to wait for everything to be pre-loaded.

Our XAML compiler has been optimized to produce less MSIL code. This means that there is less code to JIT. That also means your assemblies will be smaller, saving memory and reducing the footprint. Applications also load faster.

We have also optimised our styling system and renderer. Even on low powered devices it's now possible to load very quickly and render at very high frame rates.

These performance gains are particularly noticeable on low powered and embedded devices.

Why should you use Avalonia?

Avalonia is quickly becoming the choice of many big companies who need a UI platform they can depend on. Over the last 2 years Avalonia has successfully maintained its 0.10.x api, and proven it can provide a stable api that is enforced with api analysis and automated testing.

When 11.0 is released you will be able to rely on the api and know that it will remain stable and supported for years to come.

There are now a huge number of real applications in production. Avalonia is supported by a company (AvaloniaUI OU). We have been providing porting services and commercial support to our customers for over 2 years.

If you need support and guarantees please contact team@avaloniaui.net for more information.

Find us on...
Telegram: https://t.me/Avalonia
Twitter: https://twitter.com/avaloniaui
Github: https://github.com/AvaloniaUI/Avalonia
www: http://avaloniaui.net/

Avalonia platform support - why it's simple

Mike James — Fri, 03 Jun 2022 10:25:27 +0000

I recently came across a developer discussing Avalonia on Discord who was conflating the wide range of platforms Avalonia supports with a significant increase in development effort. I thought it would be interesting to briefly explore how Avalonia works and explain why bringing Avalonia to new platforms isn't nearly as involved as some might imagine.

Background

How does it compare to MAUI?
Before we go too far, it's essential to understand that Avalonia works very differently from frameworks like MAUI (or Xamarin.Forms), which uses a platform's native UI toolkit, providing a common API across all the supported platforms. MAUI is less a UI toolkit; more an abstraction layer over existing toolkits. The task of rendering the UI and handling user interactions isn't something the MAUI development team needs to worry about, as the device's UI toolkit is responsible for this. Instead, the primary problem for the MAUI development team has been creating an abstraction that conceals the wildly different UI toolkits, each with its quirks. Think of MAUI as a wrapper that provides native controls in an easy to use and lowest common denominator API.

Avalonia - Making Pixel-Perfect Apps

Having established how MAUI works, let's examine how Avalonia's architecture and approach differ. It's worth knowing that Avalonia is in good company in its design and isn't altogether unique as it shares similarities with how Google's Flutter UI toolkit works.

The most significant similarity is that Avalonia also utilises its own renderer, backed either by Skia or Direct2D. The renderer is responsible for drawing the entire application, allowing Avalonia to avoid depending on a device's UI toolkit.

To illustrate why this is significant, we should consider embedded and low-powered devices. Avalonia has become particularly popular among manufacturers producing touch-based embedded industrial devices.

We've found that they'll often use Linux, opting not to install a desktop environment, which would waste the limited storage, memory and CPU available on their low-powered devices. They can do this because Avalonia supports both accelerated rendering via Direct Rendering Manager and a software framebuffer. Given it’s using the same kernel API’s used internally by Xorg and Wayland compositors, it essentially replaces Xorg/Wayland, gaining exclusive access to the graphics hardware.

Beyond industrial device manufacturing, this approach brings countless other benefits, such as ensuring that an app looks and behaves identically across all the supported platforms. The ability to customise any part of the UI for any particular platform is maintained and is as simple as altering XAML styles. With Avalonia, creating great-looking, cross-platform apps without needing to use platform-specific UI APIs for the various devices you're supporting is easy. It's the essence of "write once, run everywhere".

Architecture

The architecture diagram below gives a good overview of how Avalonia works. Note that the majority of functionality in Avalonia resides in a netstandard2.0 project!

Rendering an application's user interface is just one piece of the puzzle. Avalonia also needs to handle elements such as wiring up the clipboard, windowing, cursors, hardware acceleration and input events. These pieces of the puzzle are required to facilitate Avalonia on a new platform.

Platform Support

Regardless of the intricacies required to create a UI toolkit, between 10 and 15 percent of the Avalonia code relates to facilitating the platforms. Most of the code is agnostic to any platform, meaning it's relatively easy for us to bring Avalonia support to new platforms when we want.

At the fundamental level, supporting a new platform with Avalonia requires two things; the ability to draw pixels and receive input events.

Avalonia VNC

To demonstrate this point, let's look at the Avalonia VNC platform support. While not typically considered a platform in its own right, in the context of Avalonia, VNC meets the prerequisites of being able to draw pixels and receive input events. It can thus be considered a platform!

What's especially surprising about the Avalonia VNC platform support is its implementation stands at less than 200 lines of code! It demonstrates just how little code is required to enable a new platform!

Why does Avalonia support VNC in the first place? Well, it's valuable for a few reasons, with my favourite being it enabled very early testing of web support. Before WASM with Blazor were viable options for enabling Avalonia in the browser, it was possible to run an embedded VNC server serving Avalonia content, delivering rudimentary web support.

Conclusion

While Avalonia has been historically focused on the desktop for almost a decade now, the recently released preview of iOS, Android and Web support represents a new milestone for the project. Supporting these platforms was never a technical problem or a matter of developer resources.

The developers contributing to Avalonia have helped create a cross-platform UI framework that industry leaders such as GitHub, Unity and JetBrains have come to trust. Given the project's remarkable success and massive growth in contributors, it presents an excellent opportunity to look to the future and consider how we can improve mobile and web development.

Learn More

Announcing the release of TreeDataGrid

Daniil Pavliuchyk — Tue, 29 Mar 2022 09:38:01 +0000

Our new control TreeDataGrid is now publicly available. It is 2 controls in one - DataGrid and TreeView.

Our users have been asking us for more performant version of DataGrid and TreeView type controls capable of displaying huge datasets. We started to develop this control internally a long time ago. This control is already more performant than it's analogues from the main repository. It supports virtualisation, everything is strongly typed, and we are even using internal experimental features like TypedBindings. TreeDataGrid is still far behind DataGrid from the main repository in terms of features, but our commercial customers do use this control in their applications, and they are happy with it! As of the time of writing it’s great for display lots of data, we have not yet however, added the ability to edit said data.

Controls like these take a lot of expertise, dedication, and time to design and build. We have wrestled with the idea to commercialise this control or to make it publicly available for free.
In the end we have decided to allow anyone to use it for free under the MIT license.

However, will ask that support for these controls (issues and pull requests) can only be provided to paying customers. (See our support packages for more information).

Documentation is available on our site and NuGet package is also publicly available!

Please consider using this control and share your impressions in our Twitter and in our Telegram chat.

Avalonia - Mobile is here

Dan Walmsley — Thu, 17 Mar 2022 12:59:09 +0000

Today I appeared on the famous dotnet rocks podcast.

We discussed how Avalonia is gravitating from Desktop development to include Mobile development.

As promised I have readied some templates and documentation for those early adoptors to begin testing and discovering the new possibilities this brings to Avalonia.

I have put together the following to help you get started:

A sample application "Wordle-onia"

This simple port of Wordle can run on Desktop, Browser, iOS and Android.

Dotnet templates to get you started easily.

dotnet new -i avalonia.templates
dotnet new avalonia.xplat

Some documentation to help you get started and understand how to use the templates.

Please remember although Avalonia is a production ready environment on Desktop, we are entering the early phases for mobile. We believe now is the time that you can see the true potential of Avalonia on mobile and the performance is demonstrably excellent.

However there is still work to be done ahead of our 11.0 release planned for early Summer.

As always if you have any issues with the docs or templates.

Please join us on our telegram group so we can resolve any issues.

Have fun! Dan

Nick Polyak - Thoughts on Avalonia

Dan Walmsley — Wed, 09 Mar 2022 15:26:53 +0000

Nick Polyak is a software architect, developer, and educator.

He has written many award-winning articles on CodeProject about programming, software architecture, design patterns, and more recently many articles about Avalonia.

Nick wrote one of the first MVVM pattern tutorials that I used when learning to work with WPF many years ago.

I caught up with Nick to get his thoughts on Avalonia.

When did you first discover Avalonia and what have you used it for since then?

My path to Avalonia developed over many years. When WPF was released I immediately fell in love with the groundbreaking new framework. This was because WPF brought many new concepts that are very powerful for UI development for example:

Visual and Logical Trees
Attached or Dependency Properties
Attached Routed Events
Bindings and the Related MVVM pattern
ControlTemplates
DataTemplates
Styles
Behaviors

Once Silverlight came along it opened up some new possibilities. It had almost all the features of WPF and could run in the browser, Windows, Linux, Mac.

Unfortunately, Microsoft abandoned Silverlight and that was the end of my cross-platform WPF ambitions.

What came next, frameworks like UWP and Xamarin always compromised the power of WPF, important features were left out, and even considering the web frameworks nothing came close to WPF.

Since then, I continued using WPF on Windows, at the same time looking for other frameworks both within the Microsoft universe and from the Open Source community.

About 4 years ago, I stumbled across Avalonia. I was not sure initially about the maturity of the framework (4 years ago it was in a much different place to today) so I kept an eye on the project and waited for it to develop.

Recently, I began to work on a contract with a hedge fund company. They needed a desktop UI application running both on Windows and Linux. I tried Avalonia again and became convinced that the framework was quite mature for both platforms.

Avalonia is the first framework I have discovered that not only matches WPFs concepts and APIs but in many respects exceeds them. They even fixed some of the bugs and problems that WPF had!

What are the advantages Avalonia UI has?

Avalonia provides you with the best powers of UI development combined with ease of usage. Additionally, Avalonia is truly multiplatform and your apps will run on Windows, Linux, and Mac with it.

Recently, Avalonia also released a Blazor-based WebAssembly version which allows running Avalonia apps on major browsers at any platform they support.

I'm told that mobile support is coming very soon also.

In the introduction section of my article Multiplatform UI Coding with AvaloniaUI in Easy Samples. Part 1 - AvaloniaUI Building Blocks I explain why I believe that Avalonia is better, more powerful, and easier to program than other frameworks including UWP, Xamarin, or Web-based technologies.

In addition to implementing all the WPF concepts mentioned above, Avalonia also utilizes some concepts that had not yet been discovered by the time WPF was created, for example, concepts coming from Reactive Extensions. As a result, their bindings and routed events are more powerful and less buggy than those of WPF.

In short, Avalonia is a multiplatform WPF++ that also runs in all major browsers.

Just like WPF (and unlike Web and Xamarin programming) Avalonia is very flexible and compositional. An experienced WPF or Avalonia software engineer can compose any control to consist of any primitives he wants, e.g. a Button or ComboBox (dropdown) can be composed of multiple images, borders, shapes, or text. The Avalonia visual tree is built with real primitives, like Borders, Images, Shapes, or TextBlocks. By contrast, in Xamarin and Web programming the visual tree (or HTML DOM) ends with much coarser (more complex) items like basic controls including buttons or dropdowns themselves. Correspondingly control customization is much easier and more powerful in Avalonia.

Now that Microsoft has open-sourced .NET, Avalonia is the missing piece that enables multiplatform .NET UI development a reality.

As someone who helps educate about software development, why should people learn to use Avalonia, and do you think it is easy to pick up?

For people with expertise in WPF, Silverlight, or UWP adapting to Avalonia is a breeze. In particular, after working with Avalonia for two weeks I figured out the most important differences between Avalonia and WPF and became capable of developing in Avalonia as fast as in WPF.

For people with no previous experience with any of the above frameworks, there will be a learning curve, which I believe they will have to go through anyways if they want to learn best practices and important concepts applicable to any UI development.

Those who worked with Xamarin previously will find many familiar concepts only implemented in a more powerful and flexible way with the added benefit of being easier to use.

For people with experience in Angular, the bindings, data templates, and MVVM concepts should be familiar, while those who know React, should be somewhat familiar with the concept of lookless controls and the hierarchical composition of controls and views.

How has the response been to your articles? I noticed you won the "Top C# article" award many times on CodeProject?

The response to my articles has been very positive. Based on CodeProject statistics, my articles were read by tens of thousands of people, and most of those who vote for the articles - give me the highest grade.

Many of my articles were voted to be the best of the month.

Due to the success of my Avalonia articles I have been selected as one of CodeProject's MVAs (Most Valued Authors) for 2022.

Based on the above, I do think that Avalonia has a great future ahead, it's getting popular by the day and will continue to grow.

What do you think the future will bring for Avalonia?

Even at present, there is no other multiplatform framework for building desktop applications that can come even close to Avalonia.

I believe that Avalonia has great potential and the key to unlocking this potential is better public relations (social media and marketing), continuing to improve the documentation, and fixing some well-known issues.

Also, I think it is very important to further stabilize the browser version and to allow mobile development in Avalonia both for Android and iOS, starting perhaps with Android.

Where should people go to find your articles, projects, code?

Since starting to work with Avalonia, I have built an open-source multiplatform docking framework for Avalonia called UniDock; it supports tabbing and stacking multiple windows. It is quite mature now and has been used in several projects already and (from my point of view) has more features and better functionality than WPF-based frameworks like AvalonDock, or comparable WPF Docking controls from professional control vendors. The main article detailing the UniDock functionality is UniDock - A New Multiplatform UI Docking Framework. UniDock Power Features.

I also built and released open-source tools for theming and localizing Avalonia applications. See my article: Theming and Localization Functionality for Multiplatform Avalonia UI Framework for more information.

There are several tutorials that I have published intending to teach Avalonia to beginners and demonstrate the beauty of building with Avalonia and related concepts.

Here are the links to those articles in the same order in which they should be read:

Additionally, I have published on Github NP.Avalonia.Visuals an open-source package containing some important behaviors, utilities, and controls, with accompanying article. It provides the following controls:

CustomWindow
AutoGrid
LabeledControl
More functionality, including some very useful utilities and behaviors, will be presented in future articles.

Case Study - Fluent Search

Dan Walmsley — Fri, 11 Feb 2022 23:14:44 +0000

Adir Hudayfi is a Microsoft engineer by day, and by night he works on Fluent Search an application that gives a Spotlight like experience on Windows. We caught up with Adir to find out more.

Please tell us about your project Fluent Search? What is it, who is it for? What can it do?

Fluent Search, as you might’ve guessed, is a search app.
The main goal of the app is to improve the productivity of its users, and it’s doing it by searching in all computer resources extremely fast.

By all resources, I mean everything – apps, windows, files, browser history/bookmarks, screen text, in-app content like tabs, links, and the ability to extend itself using a no-code UI platform to build extensions.

Fluent Search provides a full-screen search which gives the ability to use the computer with a keyboard only.

I aimed for Fluent Search to provide a fluent and fast experience for its users, that's why performance was super important. Avalonia has a unique architecture, everything is pluggable, renderer, style system, etc. This means that I was able to provide optimisations specific to my application, enabling performance unachievable elsewhere.

You built Fluent Search primarily for Windows, why was Avalonia a good choice for a Windows-only application? Should others consider Windows-only applications look at Avalonia?

Yes, absolutely. When a developer thinks about a cross-platform framework they think that there will be a downside, whether it’s performance or visuals, but that’s not the case with Avalonia.

As a developer, I always aspire to use the best tech that fits the project I am working on.

For most of the development of Fluent Search the UI was able to run on both Avalonia and WPF (UWP was straight up not an option). My testing showed that Avalonia performed far better, and gave me more modern visuals with its built-in with support for Windows Composition rendering.

I believe that Avalonia is currently the best option for .NET developers looking to develop a new desktop app that is not primarily a touch focused app. It is as flexible as WPF, while it looks as great as UWP/WinUI with Fluent design and it is also actively maintained.

Most new Windows app developers are looking for a fresh design that matches the Fluent design system, so I am sure Avalonia will be great for them. Many Fluent Search users still think the app was built using UWP.

I actually participated in "Launch 2021", it is an annual event for showcasing Windows applications. Its normally reserved only for UWP applications, however now it is open to all Fluent design applications. Many people were surprised that Fluent Search was already taking advantages of new Windows 11 features like Mica material effect (this was before it was available in UWP).

Did you have any difficulties working with Avalonia and where did you turn to when you needed help?

As a WPF developer, I had an easy time to start using Avalonia, once you realise that 99% of the WPF guides apply to Avalonia as well you will find a wealth of WPF and Avalonia based material online that can all be used.

I did encounter a few issues through the years, as I have been using Avalonia since its alpha days, however the community was always active, bugs get addressed extremely fast and since it’s open-source I had many chances to add new features that I needed like the new Windows 11 Mica effect one week after its release.

All libraries or 3rd party controls that I needed, graphing library, html rendering, rich text editor, were all available for Avalonia.

How do you feel about the future of Avalonia and will you use it in other projects that you work on?

I feel confident thinking about the future of Avalonia, as someone who’s been using it since its early days, I am happy to see it finally getting recognition, like the recently added full support in JetBrains Rider and adoption by industry leaders like Unity (PlasticSCM).

I shall keep using Avalonia for some new Windows-only projects I have in mind, I hope that other Windows app developers will look at Avalonia as it is a great option for new Windows only applications and also for modernising existing ones.

You can find out more about Fluent Search here.