AgentSkillsCN

avalonia-app-builder

使用 C# 构建、重构、调试并审查 AvaloniaUI 桌面应用程序。当项目需求中提及 Avalonia、.axaml 视图、XAML 界面、ViewModel 或 ViewLocator 绑定、编译时绑定与 x:DataType、CommunityToolkit.Mvvm 中的 [ObservableProperty] 部分属性、ResourceDictionary.ThemeDictionaries、StyledProperty 或 DirectProperty 的使用，或是 Avalonia 的样式/主题规范时，可选用此工具。

SKILL.md
--- frontmatter
name: avalonia-app-builder
description: Build, refactor, debug, and review AvaloniaUI desktop applications in C#. Use when requests mention Avalonia, .axaml views, XAML UI, ViewModel or ViewLocator wiring, compiled bindings and x:DataType, CommunityToolkit.Mvvm [ObservableProperty] partial properties, ResourceDictionary.ThemeDictionaries, StyledProperty or DirectProperty usage, or Avalonia styling/theming conventions.

Avalonia App Builder

Workflow

  1. •Confirm project conventions before coding.
  2. •Implement UI in Avalonia XAML (not control construction in code-behind).
  3. •Implement view-model state with CommunityToolkit.Mvvm partial observable properties.
  4. •Wire views/view-models using ViewLocator naming conventions.
  5. •Apply binding and theming rules.
  6. •Validate class/member ordering and compiled-binding coverage.

Core Conventions

UI and XAML

  • •Use Avalonia-specific XAML for layout and visuals.
  • •Avoid creating controls in code-behind unless explicitly required by the user.
  • •Define styles/resources in dedicated dictionaries and merge them in App.axaml.
  • •Use StaticResource for immutable values and DynamicResource only when runtime updates are needed.
  • •For light/dark resources, use:
xaml
<ResourceDictionary.ThemeDictionaries>
  <!-- theme dictionaries -->
</ResourceDictionary.ThemeDictionaries>

MVVM and Properties

  • •Use CommunityToolkit.Mvvm version >= 8.4.0 patterns.
  • •Define observable properties as partial properties:
csharp
[ObservableProperty]
public partial string Title { get; set; } = string.Empty;
  • •Prefer one-way bindings unless user input must update the view-model.

Binding Rules

  • •Use compiled bindings only. Set explicit x:DataType on all binding scopes:
    • •Views
    • •DataTemplates
    • •Control themes
    • •Resource dictionaries where bindings are used
  • •Do not write logical expressions in bindings (for example, && or combined conditions).
  • •Boolean inversion with ! is allowed for a single bound boolean:
    • •Valid: {Binding !IsConnecting}
    • •Invalid: {Binding !IsConnecting && !IsUpdating}

ViewLocator Conventions

  • •Respect ViewLocator naming:
    • •MyViewModel resolves to MyView.axaml
  • •Keep view-model and view names aligned to avoid runtime lookup failures.

Custom Controls

  • •Use StyledProperty only when the value must participate in styling.
  • •Prefer DirectProperty for non-styled properties.
  • •Prefer custom controls or control re-templating for strong UX, instead of CRUD-like default layouts.

C# Member Ordering

Order members by access level and member type. Use this structure:

  1. •public members
  2. •internal members
  3. •protected members
  4. •private members

Within each access level, order by:

  1. •fields
  2. •constructors
  3. •properties
  4. •commands
  5. •events
  6. •methods

Delivery Checklist

Before finishing, verify:

  • •All new/changed UI is written in Avalonia XAML.
  • •All bindings are compiled and have correct x:DataType scopes.
  • •No invalid logical binding expressions were introduced.
  • •View/view-model names follow ViewLocator convention.
  • •Theme resources use ResourceDictionary.ThemeDictionaries where needed.
  • •View-model observable properties use toolkit partial-property style.
  • •Member ordering follows the required class layout.

Reference