ArionUI for .NET desktop
Pure C#, GPU by default, Avalonia, WPF and WinForms.
ArionUI does not build a control for each row. It draws what fits on the screen, from one Skia renderer shared by all three hosts — the same data as a table, a card board, a tree, a pivot or a chart, and now the rest of the window: boards, style sheets and drawn controls.
dotnet add package ArionUI.Rendering.Avalonia --prerelease
Get started Download the demo Windows x64 GitHub
Measured, not estimated
Median cost of one frame while scrolling with the mouse wheel. Four bars, two row counts, two hosts — and the difference between a thousand rows and a million is a twentieth of a millisecond.
3,312
automated tests in five suites, all green on the same day
0
UI controls created per row — the engine draws cells, it does not instantiate them
1 → 3
one Skia renderer behind the Avalonia, WPF and WinForms hosts; GPU by default, a CPU path that repaints only the newly scrolled strip when no GPU is available
Board & Styling · preview
A layout grid like CSS grid, typed style sheets with a cascade, drawn controls — and any grid, chart or 3D view as a tile. The same engine, in pure C#, on all three hosts.
var figures = new Board
{
// four across, or two by two when narrow
Columns = [Track.AutoFit(min: 185, balance: true)],
ColumnGap = 16,
RowGap = 16,
};
figures.StyleSheet = new StyleSheet
{
{ Select.Class("kpi"),
new ArionStyle { Transition = ArionTransition.Standard } },
{ Select.Class("kpi").Hover,
new ArionStyle { Lift = 3, BorderColor = Tokens.Accent } },
};
figures.Flow(revenue, classes: "card kpi")
.Flow(orders, classes: "card kpi")
.Flow(conversion, classes: "card kpi");
grid.MainView = new BoardView(figures);Board.WhenExplain for the cascadeArionControlSurface in any windowOne engine, many views
A view is an object you assign, not a mode you configure. Every tile below is a screenshot of the showcase app; the badge says whether the view is part of the open engine or a Pro package.
All tiles: ArionUI showcase 0.1.0-preview.1 on the Avalonia host, scenes “One engine, every view”, “Data grid”, “Tree”, “Pivot”, “Formatting & markers”, “Surface 3D”, “Point cloud”, “Timeline” and “Heatmap”, each captured in the light and the dark theme.
Who it is for
That do not want to move to the web. ArionUI goes into the existing window panel by panel; the business logic of the old forms stays where it is.
The showcase on WinForms: an ordinary Form, every visible part drawn by ArionUI
Channel walls, signal views and order books that update many times a second and still sort, filter and scroll — drawn only where something changed.
“Channel wall” scene: 48 channels at 30 updates a second, Avalonia host
That want the data grid and the dashboard around it from one hand: the same theme, the same keyboard model, the same renderer for the table and the page.
“Feed” scene: 10,000 cards, Avalonia host
Swap the grid first, then a panel, then the shell — the old forms keep working the whole time. The guide shows the three paths with code that exists today, and names what is still planned.
One renderer, three hosts
Avalonia, WPF and WinForms each map input, provide a surface and a frame clock. Layout, scroll physics, interaction and drawing live below them, once — which is why the hosts behave alike and why ArionUI.Core has no UI-framework reference at all.
ArionUI.Rendering.*Hosts. Avalonia and WPF as packages, WinForms from source. Input mapping, a surface, a frame clock.ArionUI.Rendering.SkiaThe renderer. Frame renderer, glyph cache, shaped text with font fallback; the GPU blit pipeline. One for every host.ArionUI.GpuGPU layer. OpenGL ES 3.0 through a host-supplied loader, offscreen targets, shaders.ArionUI.GridThe grid. Presenter, panes, zones, accessibility, the consumer API ArionGridApi. Draws only through IRenderSurface.ArionUI.PresentationViews and columns. Table, cards, tree; the cell composition model; theming.ArionUI.CoreThe engine. Virtualization, layout solver, scroll physics, data sources. No Avalonia, WPF or Skia type anywhere in it.Open core
The engine and the grid are Apache-2.0 on GitHub. The Pro modules are NuGet packages without source — free during the preview, also commercially, without a key or a watermark.
Everything a data grid is expected to do, on one renderer for three hosts.
Nine packages that join with one call each and build only on the public surface of the engine.
It is an early preview: the API still moves, and the things it cannot do yet — touch gestures, a mirrored right-to-left layout, IME pre-edit, the WinForms host as a package — are listed rather than discovered, and what is coming is on the roadmap.
Add the host package and declare your columns, or download the showcase — every Core and Pro scene in one window, nothing to install.