This week has been a crazy deep dive on Avalonia. I’ve managed to spend over 30 hours on it and related projects. Like with any new thing you learn things that were initially confusing have become more second nature. I think part of that is that I more than doubled the amount of time working with it in a pretty focused period of time. There were certain points where things were just coming together almost automatically in my mind. At one point everything was just humming but yesterday I hit a good sized roadblock trying to learn some more complex behaviors. It’s a common problem when learning anything, or even running. You hit this point when all of a sudden everything is just moving in complete efficiency and it starts feeling effortless. It can be euphoric, however like anything euphoric it wears off and a reality will set in eventually. Yesterday it was getting my face cracked trying to get a TreeView control working and getting notifications of event changes within DataGrids properly percolating around. To be fair this is getting into using this in more complicated ways which means that the simple responses in the developer assistance area is going to get harder and harder. Sometimes the answer is going to be “it depends” or “it can’t do that” or even “I think it should work like this but not sure”. I’m still going through the guantlet on it but still I’m stoked by the entire development experience, have a few applications I want to write in it, and am looking forward to contributing to the project.

When doing visual design of forms (or in this case views) it’s often best to see what it looks like with real data. Just like with mocking data in automated tests it’s possible to use a built-in XAML feature to achieve the same thing with graphical editors. It’s a XAML field called Design.DataContext. We’ll explore that here through the standard default auto-generated MVVM application which you can follow along how to create here. To see the final solution you’ll get at the checkout The Avalonia Example Repository and look at the DesignDataExample or browse directly here.

Getting started with a new library, framework, or development system requires two important things: documentation and code samples. With both of those a developer has enough to start fiddling with things and get bootstrapped. Code samples without documentation can be like searching a dark room without a light but is doable Documentation without samples can be far more difficult than that. In fact for more complicated APIs it can be impossible without source code, which I guess is sort of code samples in and of themselves. For a lot of projects the code samples I go to are the unit/automated tests. What better place to see how the library is used than in there. However having actual code samples, especially for more complicated libraries, is even better. In the case of Avalonia the project has shipped a “controls catalog” as part of their mainline source for a while now. However now you don’t have to pull down and build the full Avalonia source code to get it since there is a stand alone version of it. Here’s how to use it with Rider and AvalonStudio.

In my write up on Avalonia first impressions one of the things I was most missing was a full IntelliSense/Auto-complete style system for the Avalonia XAML and the ability to create components in the IDE on Linux. “The IDE” in both of those cases was the one I had focused on which was JetBrain’s Rider IDE. When I originally wrote the article I thought there was no alternative so I’d have to use a workflow akin to doing it in a pure text editor. However as I was in the middle of editing I discovered that the Avalonia developers are actually working on a full IDE built with Avalonia called AvalonStudio. While it is in heavy development in beta and missing some key features because if it I have to say it is impressive how many features it has and how well it works already. Could it replace Rider for .NET development right now? No. Could it eventually? Maybe, but that’s not why it is interesting to me. It’s interesting to me because it has the facilities I sorely wanted in Rider but found missing: XAML IntelliSense (and preview!) and Avalonia component creation with proper namespace behaviors. So how does one go about running it?

Update (26 Mar 2019): The repository does in fact have binary installers in the releases not just source code. The Debian installer installed correctly but made a bad menu shortcut. Otherwise the net effect was that it worked as well as the method below but with less trouble. The releases are here. The binaries are under the “Assets” drop down for each release. To run it you need to edit/create a shortcut to the below command or execute it on the command line:

dotnet /opt/vitalelement/avalonstudio/bin/AvalonStudio.dll

I’ve documented the first forays into doing cross-platform .NET development with Avalonia. I’ve stated that I’m overall impressed. However what are my deeper thoughts on it?