dotnet-ui-chooser

What this skill does

# dotnet-ui-chooser

UI framework selection decision tree for .NET applications. Covers Web (Blazor Server, Blazor WebAssembly, Blazor Hybrid), cross-platform (MAUI, Uno Platform, Avalonia), and Windows-only (WinUI 3, WPF, WinForms) frameworks. Presents structured trade-off analysis across five decision factors to help teams evaluate options based on their specific constraints.

**Scope boundary:** This skill owns the framework selection decision tree and cross-framework comparison. Individual framework depth, patterns, and APIs are owned by the respective framework skills. Migration guidance between frameworks is owned by [skill:dotnet-wpf-migration].

**Out of scope:** Framework-specific implementation patterns -- see individual skills listed below. Migration paths between frameworks -- see [skill:dotnet-wpf-migration]. Desktop UI testing -- see [skill:dotnet-ui-testing-core].

Cross-references: [skill:dotnet-blazor-patterns] for Blazor hosting and render modes, [skill:dotnet-maui-development] for MAUI patterns, [skill:dotnet-uno-platform] for Uno Platform patterns, [skill:dotnet-winui] for WinUI 3 patterns, [skill:dotnet-wpf-modern] for modern WPF on .NET 8+, [skill:dotnet-winforms-basics] for WinForms modernization.

---

## Decision Tree

Use this structured flow to narrow framework choices based on project constraints. Each branch presents trade-offs rather than definitive answers -- the right choice depends on the weight your team assigns to each factor.

### Step 1: Target Platforms

The most significant constraint. Identify which platforms the application must support.

```
Target platforms?
|
+-- Web browser only
|   --> Blazor (Server, WebAssembly, or Auto)
|       See "Blazor Hosting Model Selection" below
|
+-- Windows only
|   --> WinUI 3, WPF, or WinForms
|       See "Windows Framework Selection" below
|
+-- Mobile (iOS / Android)
|   +-- Also need desktop?
|   |   +-- Yes --> MAUI or Uno Platform
|   |   +-- No  --> MAUI or Uno Platform
|   |
|   +-- Also need web?
|       +-- Yes --> Uno Platform (WASM target) or Blazor Hybrid in MAUI
|       +-- No  --> MAUI or Uno Platform
|
+-- All platforms (web + mobile + desktop)
|   --> Uno Platform (broadest reach)
|       or Blazor Hybrid in MAUI (web UI, native shell)
|
+-- Desktop cross-platform (Windows + macOS + Linux)
    --> Uno Platform or Avalonia
        MAUI supports macOS/Windows but not Linux
```

### Step 2: Team Expertise

Match frameworks to existing team skills to reduce ramp-up time.

| Team Strength | Strong Fit | Moderate Fit | Steeper Curve |
|---|---|---|---|
| WPF / WinUI XAML | WPF, WinUI 3 | Uno Platform (WinUI XAML surface) | Blazor (Razor syntax) |
| Web (HTML/CSS/JS) | Blazor | Uno Platform (WASM target) | WPF, WinUI (XAML) |
| Xamarin.Forms | MAUI (direct successor) | Uno Platform | Blazor, WPF |
| C# but no UI framework | WinForms (simplest), Blazor | MAUI | WPF, WinUI (XAML learning curve) |
| React / Angular | Blazor WebAssembly (SPA model) | Uno Platform (WASM) | WPF, WinUI |

### Step 3: UI Complexity

Match the UI requirements to framework rendering capabilities.

| UI Need | Best Fit | Also Consider |
|---|---|---|
| Rich native Windows UI (custom controls, animations) | WinUI 3, WPF | Uno Platform (WinUI surface) |
| Web-style layouts (responsive, CSS-based) | Blazor | Uno Platform (Skia rendering) |
| Simple data-entry forms, internal tools | WinForms | Blazor (Static SSR), WPF |
| Pixel-perfect cross-platform UI | Uno Platform (Skia rendering) | Avalonia |
| Platform-native look per OS | MAUI (native controls) | Uno Platform (native mode) |
| Embedded web content in desktop/mobile app | Blazor Hybrid in MAUI | Blazor Hybrid in WPF/WinForms |

### Step 4: Performance Needs

Framework rendering architecture affects performance characteristics.

| Performance Factor | WinUI 3 | WPF | WinForms | Blazor Server | Blazor WASM | MAUI | Uno Platform |
|---|---|---|---|---|---|---|---|
| Startup time | Fast | Fast | Fast | Fast (server) | Slow (download) | Moderate | Moderate |
| Rendering | DirectX (native) | DirectX (managed) | GDI+ | Server-side HTML | Browser DOM | Platform-native | Skia or native |
| AOT support | N/A (Windows) | N/A (Windows) | N/A (Windows) | N/A (server) | Yes (.NET 8+) | Yes (required on iOS) | Yes (WASM) |
| GPU acceleration | Yes | Yes | Limited | N/A | Browser GPU | Platform GPU | Skia GPU |
| Memory per user | Local only | Local only | Local only | Server circuit | Browser sandbox | Local only | Local only |
| Offline capable | Yes | Yes | Yes | No | Yes | Yes | Yes (native targets) |

### Step 5: Migration Path

If modernizing an existing application, the source framework constrains viable targets.

| Current Framework | Natural Target | Alternative Target | Decision Factors |
|---|---|---|---|
| UWP | WinUI 3 | Uno Platform | Windows-only: WinUI 3. Cross-platform needed: Uno Platform. |
| Xamarin.Forms | MAUI | Uno Platform | Direct API successor: MAUI. Broader platform reach: Uno Platform. |
| WPF (.NET Framework) | WPF on .NET 8+ | WinUI 3 or Uno Platform | Minimal risk: WPF .NET 8+. Modern UI: WinUI 3. Cross-platform: Uno Platform. |
| WinForms (.NET Framework) | WinForms on .NET 8+ | Blazor or WPF | Minimal risk: WinForms .NET 8+. Better UI: WPF. Web delivery: Blazor. |
| ASP.NET MVC / Razor Pages | Blazor (Static SSR) | Stay on Razor Pages | Interactive needs: Blazor. Content-heavy: Razor Pages is still valid. |
| React / Angular SPA | Blazor WebAssembly | Keep existing SPA | .NET-only team: Blazor. Existing JS team: keep SPA. |

---

## Blazor Hosting Model Selection

When Blazor is the target, select a hosting model based on interactivity needs, deployment constraints, and scale.

| Concern | Static SSR | InteractiveServer | InteractiveWebAssembly | InteractiveAuto | Blazor Hybrid |
|---|---|---|---|---|---|
| Interactivity | Forms only | Full | Full (after download) | Full | Full (native) |
| Server required | Yes (render) | Yes (persistent circuit) | Static file host only | Yes (initial), then static | No |
| Offline | No | No | Yes | Partial | Yes |
| Scalability | High | Limited by circuits | High | High (after WASM) | N/A (local) |
| First paint | Fast | Fast | Slow (WASM download) | Fast (Server first) | Instant |
| SEO | Yes | Prerender | Prerender | Prerender | N/A |
| Best for | Content sites, simple forms | Dashboards, LOB apps | Public apps, offline PWAs | Best of both worlds | Desktop/mobile with web UI |

For detailed Blazor patterns, see [skill:dotnet-blazor-patterns].

---

## Windows Framework Selection

When the application targets Windows only, choose based on UI richness, team expertise, and modernization goals.

### Comparison Table

| Concern | WinUI 3 | WPF (.NET 8+) | WinForms (.NET 8+) |
|---|---|---|---|
| UI paradigm | Modern XAML, Fluent Design | Classic XAML, optional Fluent (.NET 9+) | Designer-driven, drag-and-drop |
| Rendering | DirectX (Windows App SDK) | DirectX (WPF layer) | GDI+ |
| MVVM support | CommunityToolkit.Mvvm | CommunityToolkit.Mvvm, mature ecosystem | Possible but not idiomatic |
| DI / Host builder | Yes | Yes | Yes (.NET 8+) |
| High-DPI | Native | Improved in .NET 8+ | PerMonitorV2 (requires config) |
| Dark mode | Native Fluent | Application.ThemeMode (.NET 9+) | Experimental (.NET 9+) |
| Touch / pen | Full support | Basic support | Limited |
| Learning curve | Moderate (XAML) | Moderate (XAML) | Low |
| Maturity | Newer (2021+) | Very mature (2006+) | Very mature (2002+) |
| UWP migration path | Direct | Indirect (XAML differences) | N/A |

### When to Choose Each

**WinUI 3** -- best for new Windows-native applications that need modern Fluent Design, touch/pen input, and the latest Windows integration (widgets, notifications, Mica). Requires Windows 10 2004+. See [skill:dotnet-winui].

**WPF on .NET 8+** -- best for teams with existing WPF expertise, applications that need the rich WPF control ecosystem, or projects migrating from WPF on .NET Framework. Fluent theme ava