50 lines
1.9 KiB
Markdown
50 lines
1.9 KiB
Markdown
# Avalonia, Zafiro & Reactive Rules
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## Avalonia UI Rules
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- **Strict Avalonia**: Never use `System.Drawing`; always use Avalonia types.
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- **Pure ViewModels**: ViewModels must **never** reference Avalonia types.
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- **Bindings Over Code-Behind**: Logic should be driven by bindings.
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- **DataTemplates**: Prefer explicit `DataTemplate`s and typed `DataContext`s.
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- **VisualStates**: Avoid using `VisualStates` unless absolutely required.
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## Zafiro Guidelines
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- **Prefer Abstractions**: Always look for existing Zafiro helpers, extension methods, and abstractions before re-implementing logic.
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- **Validation**: Use Zafiro's `ValidationRule` and validation extensions instead of ad-hoc reactive logic.
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## DynamicData & Reactive Rules
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### The Mandatory Approach
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- **Operator Preference**: Always prefer **DynamicData** operators (`Connect`, `Filter`, `Transform`, `Sort`, `Bind`, `DisposeMany`) over plain Rx operators when working with collections.
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- **Readable Pipelines**: Build and maintain pipelines as a single, readable chain.
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- **Lifecycle**: Use `DisposeWith` for lifecycle management.
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- **Minimal Subscriptions**: Subscriptions should be minimal, centralized, and strictly for side-effects.
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### Forbidden Anti-Patterns
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- **Ad-hoc Sources**: Do NOT create new `SourceList` / `SourceCache` on the fly for local problems.
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- **Logic in Subscribe**: Do NOT place business logic inside `Subscribe`.
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- **Operator Mismatch**: Do NOT use `System.Reactive` operators if a DynamicData equivalent exists.
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### Canonical Patterns
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**Validation of Dynamic Collections:**
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```csharp
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this.ValidationRule(
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StagesSource
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.Connect()
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.FilterOnObservable(stage => stage.IsValid)
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.IsEmpty(),
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b => !b,
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_ => "Stages are not valid")
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.DisposeWith(Disposables);
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```
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**Filtering Nulls:**
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Use `WhereNotNull()` in reactive pipelines.
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```csharp
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this.WhenAnyValue(x => x.DurationPreset).WhereNotNull()
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```
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