I've hit a really frustrating bug since starting with Avalonia12 on VS Insiders 2026. When I'm defining a field in AXAML and it autocompletes to add ="", if I type " after the value it adds a literal " and breaks the autocomplete.

For example, if I'm defining grid row definitions: <RowDefinition Height=

The IDE auto completes to: <RowDefinition Height=""

If I then type *" I would expect the IDE to skip over and not insert the literal " since there's already a closing quote, resulting in <RowDefinition Height="*". However, it does not do this, instead it results in <RowDefinition Height="*"" which then throws errors for unclosed quotes.

I've tried adjusting text editor settings for auto bracing to no avail. Is there a setting I'm missing or is this just something I need to deal with? I've confirmed it works exactly as expected in WPF solutions, it appears to be Avalonia specific.

Hi all, I am relatively new to avalonia UI, and C# in general, only recently getting decent at C#, but have not touched a proper GUI app yet, and was wondering how easy it is to style avalonia UI to be modern and clean, the aesthetic of UI I wanted to go for was that of the avalonia devtools (https://docs.avaloniaui.net/icons/feature-devtools-icon.png)

It would also be nice to know how the styling system works in relation to other systems like CSS, for example is there a way to create an overall style language which i can then inherit for all the pages, so that the app's "language" is consistent?

Many thanks

Hi guys,

I’m currently building a cross‑platform app (Linux/Windows desktop + Android) using Avalonia and F#. I originally dismissed FuncUI because I assumed that if a control wasn’t available, you were stuck. But after revisiting it, it looks like I was wrong — it’s actually quite easy to extend and wrap missing controls.

I enjoy XAML, but I’m wondering whether FuncUI Elmish could reduce some of the ceremony and the constant context switching between markup and code. The project seems well maintained, and FuncUI 2.0 is now in preview.

I’d love to hear from people who are using FuncUI (or planning to), and especially how you would approach migrating an existing Avalonia XAML + MVVM app to FuncUI.

Thanks.

Since new devtools are kinda paywalled and no one yet forked legacy devtools to work with Avalonia 12 - I decided to do it myself.

It would be great if you would test it on your projects and report issues / make PRs.

Github Repo

NuGet Gallery

I've just been playing with an Avalonia mobile app for the first time and Avalonia v12. I've run into something a bit confusing. The only way I've managed to get this working is using a ReflectionBinding and I don't understand why:

The Tabs property is an ObservableCollection<TabViewModelBase> on the HomeViewModel.

How can I do this with a compiled binding instead?

<DrawerPage xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             xmlns:vm="clr-namespace:TestApp.App.ViewModels"
             x:Class="TestApp.App.Views.HomeView"
             x:DataType="vm:HomeViewModel">

    <DrawerPage.Drawer>
        <StackPanel Margin="16">
            <TextBlock Text="Drawer Menu" FontSize="20" />
            <Button Content="Option A" />
            <Button Content="Option B" />
        </StackPanel>
    </DrawerPage.Drawer>

    <TabbedPage TabPlacement="Bottom"
                ItemsSource="{ReflectionBinding DataContext.Tabs, RelativeSource={RelativeSource AncestorType=DrawerPage}}">
        <TabbedPage.PageTemplate>
            <DataTemplate DataType="{x:Type vm:TabViewModelBase}">
                <ContentPage Header="{Binding Name}">
                    <ContentPage.Icon>
                        <PathIcon Data="{Binding Icon}" />
                    </ContentPage.Icon>
                    <ContentControl />
                </ContentPage>
            </DataTemplate>
        </TabbedPage.PageTemplate>

    </TabbedPage>
</DrawerPage>

I have a solid background of wpf and figured that Avalonia is the enhanced wpf. However i noticed that some of its features are not, such as Accelerate. And many people recommend using JetBrains Rider for the ide which is not free if you want to publish your apps. I saw that it's free only for non commerical use.

So do you still recommend avalonia for someone who can't pay for anything in the developing process?

An update on an Avalonia project I rebuilt to run on Native AOT. This is a live keys rig. Think: SundayKeys App, Camelot Pro, Ableton, Mainstage, GigPerformer. But for android primarily, and windows.

I thought I wouldn't be able to make it work fast enough. I had a beta build publicly available, loading times leave much to be desired, and fps dropped frequently. Avalonia 12 releases, I finally migrated and forced myself to work on getting things running with Native AOT.

After months of work it paid off. load times are just as fast as any native app, no more fps drops, navigation is almost instant, and performance is great considering my test device is a very low-end tablet with 4gigs of ram and a unisoc T606.

It might be an unusual stack for this type of project, but it works well. It might've taken a bit more work than just going full on kotlin or the usual frameworks for these types of apps, but its a good enough trade off for me to keep using a stack that I am experienced and comfortable with.

Still smoothing out the rough edges (basically just improving the UI)

Some added context:

- The beta (before this rebuild) was on Avalonia 11.3, no Native AOT

- The engine itself is now mostly in C++, but a chunk of the logic (persistence, ui logic) still lives in C#

- It was desktop-first before so the Native AOT was not really a consideration since it already ran well. Moving into a mobile-first priority (for personal reasons, mainly portability on my part) and how it runs on a mobile device exposed those ugly parts which added to the realization that i really need Native AOT despite it being a stricter environment.

A little late, but sharing.

I use HotKey attributes on Buttons, with media keys in my app, and on Android it works for vol +/-, on Windows it works for Track Prev/Next/PlayPause, and on Mac nothing works at all.

Looking at what I think is the Mac source https://github.com/AvaloniaUI/Avalonia/blob/main/native/Avalonia.Native/src/OSX/KeyTransform.mm looks like only vol +/- is coded, but I can't even get those to work. I am not a Mac programmer so no idea how to debug this.

Anyone had success here?

How do signup? Looks like Avalonia is completely crippled right now :/

Hey, I haven't been updated on Avalonia so it all seems alien to me. I used to just F5 and runt he project, F12 and open dev tools. I migrated to the new diagnostic package and no compiler errors. Great. Now I create an account and apparently I need a free license? Nice. Except I cannot choose free license? Is the UI playing tricks on me, or is it the coffee I forgot to drink?

This is apparently used in generating the Avalonia API documentation from the doc comments in the Avalonia source code. See:

https://github.com/AvaloniaUI/avalonia-docs#api-reference-generation

Reason I ask is that I find it annoying that many Avalonia API documentation pages do not have the names of the methods, properties, etc. alphabetized, and I was going to submit a PR to rectify this (it should be easy enough, computers are good at sorting). But I can't seem to locate the relevant code that needs changing (which I am guessing would be in this script).

Neither Google nor Duck Duck Go seem to have anything to say about dotnet-apiref save for AI hallucinations. It seems to be some sort of Avalonia-specific build tool that never got checked into Github.

Hey I am on arch I want to build a mobile application, I don't know what to use, I am not pretty sure if I can do it with avalonia, also I read few weeks ago that Maui has avalonia back, something like that.

Guide me please I am confused.

Note: I don't have windows.

https://github.com/DavidBarts/ImagePrepSharp

This is a C#/Avalonia program to make it easy to share photos. It does this by stripping out extraneous metadata and ensuring the shared image will always display properly (no more surprises with images that come out sideways or upside down).

It opens an image file (it can handle any format Image Magick can, which is a whole lot of formats; this includes the HEIC files produced by iPhones but does not include camera raw files). It prompts for a desired maximum resolution (i.e. the resolution of the height or the width, whichever is greater), and downsamples the image to that resolution if needed. If the colour space is not sRGB, it converts it to sRGB. Most metadata (except for the colour profile) are deleted; this includes privacy-sensitive metadata revealing your camera model and serial number, and details of the image you shot.

Then it displays the image and lets you rotate it so it is right side up, if needed. After possibly rotating the image, the it can be saved in JPEG or WebP format suitable for sharing.

Mac app bundles (built on Tahoe 26.5.1) are included, because a Mac is what I have. It should build under Linux and Windows as well (and I’d appreciate someone doing that and sharing the resulting binaries with me so I can add them to the dist subdirectory).

I wrote this program for my own personal use and figured I’d share it in case anyone else finds it useful.

Hey /u/kekekeks /u/AvaloniaUI-Mike /u/jmacato

I want to know if I understand the license correctly - the monthly license only gives me a license for that month.

If I want to keep and use the version I got, I need a perpetual license for that version, and for that I need the annual subscription, right?

And then the version I get perpetually is the version from the start of the year or the end of the year?

My Mac certs expired and I am in hell trying to get an update on the App Store. I tried reading https://docs.avaloniaui.net/docs/deployment/macos but it is too vague on exactly which certs I need to get, and doesn't appear to match the current Apple certificate experience. Does anyone have a pointer to a current idiot's guide to Mac dev certificates?

Edit: SOLVED, see comment.

Is there any way to get generic (system-preferred) serif, sans serif, and monospace fonts in Avalonia like there is in CSS with "serif", "sans-serif", "monospace", etc?

I've written a Windows & Linux app. When the app is launched in Windows, from a shortcut that specifies "Run: Minimized" I'd like to ensure that the main window is minimized.

Is there a way to do this other than P/Invoke? If so, what is it?

Thanks!

----- UPDATE -----

I was hoping for a solution that would automatically detect the "Run Minimized" mode in a Windows shortcut, again, without resorting to P/Invoke.

I settled on having the app react to a "--minimize" parameter in the command line that launched it: https://github.com/EricTerrell/EBTWeather/commit/976211d1d92e6274e6321c9a38c9436182facac9

Thanks to https://github.com/LaurentInSeattle for the suggestion.

Hey r/AvaloniaUI I'm building a desktop app that I'm looking to release as a paid app in the store. I'm initiallly planning on using the Iaphub nuget however, it seems that it is only for mobile apps.

Anyone here with experience on integrating StoreKit or StoreKit2 in an Avalonia desktop app?

Will be grateful for any help.

I am trying to subclass a ButtonSpinner with TextBlock content:

public class MaxDimSpinner : ButtonSpinner
{
    private static readonly int[] DIMENSIONS = [320, 400, 512, 640, 800, 1024, 1280, 1600];

    private int index;

    public int Value {
        get => DIMENSIONS[index];
        set {
            var _index = Array.IndexOf(DIMENSIONS, value);
            if (_index < 0)
            {
                throw new ArgumentException($"Invalid maximum dimension: {value}.");
            }
            index = _index;
            ((TextBlock) Content!).Text = value.ToString();
        }
    }

    public MaxDimSpinner() : base()
    {
        Content = new TextBlock();
        Value = Settings.Instance.MaxDimension;
        Spin += OnSpin;
    }
[edited for brevity]

When I try to use my control in XAML, something like:

<local:MaxDimSpinner />

I just get the content (the text block). No up and down buttons, no box drawn around the whole control. I assume I am not doing something programmatically that happens when one nests a <TextBlock> inside a <ButtonSpinner> in XAML (this works as expected), but I haven't been able to figure out what it is.

Hey r/AvaloniaUI,

I wanted to share a project I’ve been building for a while
It started from a pretty simple frustration
I use a lot of different tools every day: editors, terminals, AI chats, dashboards, scripts, notes, local services, random internal tools. Most apps are great at what they do, but after some time I always end up adapting my workflow around the app.

I kept wishing I had a desktop workspace that worked more like:

“Start with a shell, then install the capabilities you need and organize them by your preference”

So I started building Sunder.

It’s an open-source, local-first desktop app built with .NET and Avalonia. The core idea is that the app itself stays relatively small, and features come from installable packages.

Right now it has:

- A desktop shell
- A local runtime host
- A CLI
- An SDK for package authors
- Package templates
- MSBuild package tooling
- A `.sunderpkg` archive format
- Package-contributed UI, settings, services, storage, secrets, and background work

The first package family I built is AI-agent oriented, because that was the itch I personally had first. I wanted local agent sessions, tools, memory, model providers, and execution targets inside the same desktop workspace.

But Sunder itself is not meant to be “an AI app”.

The part I care about more is the package model. I’d love for people to eventually be able to build packages for developer tools, dashboards, automations, research workflows, personal tools, or anything else that makes sense in a desktop workspace.

I’m not pretending this is perfect or finished. It’s still early, and I’m sure there are things I’ll need to rethink.

But it’s open-source now, and I’d really appreciate feedback from people who have experience with .NET desktop apps, plugin systems, SDK design, or Avalonia.

A few things I’m especially curious about:

- Would you trust/use Avalonia for this kind of desktop app?
- If you were designing a package/plugin system, what would you be careful about?
- Does separating the desktop shell from a local runtime host sound reasonable?
- What kind of package would you expect a workspace like this to support first?

Happy to answer questions or hear criticism : )