CSharpForMarkup

Not a user experience answer per se but there is https://github.com/VincentH-Net/CSharpForMarkup which allows to define UI declaratively in a style that is even closer to SwiftUI than "Uno C# markup".

Interestingly enough, in practice, there are various declarative SwiftUI-style nuget packages for Avalonia[0][1][2] and Uno[3]. You don't actually have to touch XML if you don't want to. Edit: as someone else noted, the website itself links to a built-in option to do so as well - https://platform.uno/c-markup/ [0] https://github.com/AvaloniaUI/Avalonia.Markup.Declarative [1] https://github.com/wieslawsoltes/NXUI [2] (F#) https://github.com/fsprojects/Avalonia.FuncUI [3] https://github.com/VincentH-Net/CSharpForMarkup

You can use CSharpForMarkup with WPF, WinUI 3, Uno Platform. with AvaloniaUI and Maui coming and possibly Blazor. https://github.com/VincentH-Net/CSharpForMarkup

To manage mental mapping of what is being drawn, I keep methods that create widget trees short. My rule of thumb is that whole method has to comfortably fit the screen at once. For each section of the main tree I create a static function that returns a branch of the tree. These functions have descriptive names that help you visualize what element each function builds. If a tree inside a function is long, it is broken down in the same way. There are some fluent extensions (for Xamarin.Forms and probably future MAUI) that help you build UI in declarative fashion with C#. Same extensions could be created for other frameworks. https://devblogs.microsoft.com/xamarin/c-sharp-markup-for-xa... https://github.com/VincentH-Net/CSharpForMarkup For reusable custom widgets that can't be done with a static function, I create new classes with their own