ToolingHot Design
The Problem It Solves

When a team migrates a WPF page to Uno Platform, the most common review-loop friction is "the layout is close but not right." A margin is off, a column width is wrong, a button is misaligned in dark mode. The traditional loop is: edit XAML, save, rebuild, run, look, repeat. Hot Design collapses that loop. The engineer or designer opens the running migrated page, fixes the layout in place, and the source updates as they go. For a team migrating 15 to 50 pages, the time saved compounds.

Agentic Composition

How It Composes with the Agentic Migration Loop

Hot Design is one of three runtime tools in the Uno Platform agentic dev loop:

  • The Uno Platform MCP gives AI agents grounded documentation knowledge.
  • The Uno App MCP gives AI agents runtime access to the visual tree, properties, and screenshots for verification.
  • Hot Design gives humans (and the Hot Design Agent) a runtime UI to edit on top of that running app.

A typical migration cycle for one page:

1 Agent generates the migrated page using the Uno Platform MCP

The agent queries docs for namespace mappings, control parity, and binding syntax. It writes MyPage.xaml and the code-behind.

2 Build passes; the app launches

Standard dotnet build. The migrated page is running with real data.

3 App MCP verifies the visual tree

The agent walks the visual tree, reads effective property values, and reports any binding or property regressions. Agent patches automatically.

4 Engineer opens Hot Design and tunes layout details

This is where Hot Design earns its place. The engineer selects a misaligned control, adjusts its margin or alignment on the live app, sees the change instantly, and moves on. No rebuild. No re-run.

5 Hot Design writes the edits back to source

The PR diff includes both the agent's translation and the human's polish. Clean separation of mechanical work and visual judgment.

6 Reviewer merges

One PR, one page, both the agent's work and the designer's corrections.

The full pattern is documented in AI-Assisted WPF Migration: What Actually Works in 2026.

Honest Limits

What Hot Design Does Not Replace

Honest framing on what is still in the IDE, not the designer:

  • Code-behind logic. Edited in the IDE.
  • ViewModel changes. Edited in the IDE.
  • Control templates and complex visual states. Best edited in XAML source with Hot Reload.
  • Build configuration, target frameworks, MSBuild targets. IDE.
  • Tests. IDE.

Hot Design is for layout, controls, properties, styles, and resources. The bulk of what a WPF designer touches when a developer says "tweak the UI." Code logic stays where it always was.

Framework Selection

Where This Fits in Framework Selection

For WPF teams evaluating cross-platform targets in 2026, the runtime designer story should be a named criterion:

FrameworkRuntime Visual DesignerNotes
WPF (stay)Visual Studio XAML DesignerWindows-only, design-time
WinUI 3Visual Studio XAML DesignerWindows-only, design-time
Uno PlatformHot DesignRuntime, six platforms, writes back to source
.NET MAUIHot Reload (no designer in the same sense)Updates running app on file save
Independent cross-platform XAMLPreview tooling and Hot Reload patternsVerify per framework at time of evaluation

If your team's investment in the WPF designer is one of the larger reasons the migration feels hard, Hot Design is the criterion that often tips the framework decision.

Get Started

Install the Uno Platform Studio Pro 15-day trial and run Hot Design on a sample Uno Platform app to see the runtime-designer experience end-to-end. For an existing WPF app, embed one Uno Platform page using Uno Islands and open Hot Design on the embedded page; you will see the runtime designer working inside your existing WPF host.

Sources & Related