dotnet__skills/tests/dotnet-maui/maui-data-binding/eval.vally.yaml

name: maui-data-binding
description: Evaluates the dotnet-maui/maui-data-binding skill
type: capability
config:
  timeout: 2m
stimuli:
  - name: Set up compiled bindings with x:DataType on a page
    prompt: |
      I have a .NET MAUI ContentPage called SettingsPage.xaml that currently uses
      plain bindings with no x:DataType. The page's BindingContext is a
      SettingsViewModel with properties: string Theme, bool NotificationsEnabled,
      and int FontSize. Convert this page to use compiled bindings and tell me
      how to catch binding errors at build time.
    graders:
      - type: output-contains
        config:
          substring: x:DataType
      - type: output-matches
        config:
          pattern: (?i)SettingsViewModel
      - type: output-matches
        config:
          pattern: XC0022|XC0025|WarningsAsErrors
      - type: prompt
    rubric:
      - Places x:DataType on the ContentPage root element pointing to SettingsViewModel
      - Does not scatter x:DataType on child elements or use x:DataType='x:Object'
      - Recommends enabling XC0022 and/or XC0025 as warnings-as-errors in the .csproj
      - Explains that compiled bindings are faster and required for NativeAOT/trimming
  - name: Implement MVVM ViewModel with ObservableObject
    prompt: |
      I need to create a ProductDetailViewModel for a .NET MAUI app. It should
      have properties for Name (string), Price (decimal), IsAvailable (bool),
      and a LoadCommand that fetches data asynchronously. Show me how to
      implement this with proper change notification so bindings update the UI.
    graders:
      - type: output-matches
        config:
          pattern: (?i)ObservableObject|INotifyPropertyChanged
      - type: output-matches
        config:
          pattern: (?i)ObservableProperty|PropertyChanged
      - type: output-matches
        config:
          pattern: (?i)RelayCommand|ICommand
      - type: prompt
    rubric:
      - Uses CommunityToolkit.Mvvm ObservableObject with [ObservableProperty] or implements INotifyPropertyChanged
        manually
      - "Includes all four members: Name, Price, IsAvailable, and a load command"
      - Shows how the generated properties raise PropertyChanged automatically when using the toolkit
      - Does not use a base class that doesn't implement INotifyPropertyChanged
  - name: Create and use an IValueConverter
    prompt: |
      In my .NET MAUI app I have a status field that is an enum:
      enum OrderStatus { Pending, Shipped, Delivered, Cancelled }.
      I want to display a different color for each status in a Label's TextColor.
      Show me how to create a value converter and wire it up in XAML.
    graders:
      - type: output-contains
        config:
          substring: IValueConverter
      - type: output-matches
        config:
          pattern: (?i)Convert
      - type: output-matches
        config:
          pattern: (?i)StaticResource|x:Key
      - type: prompt
    rubric:
      - Implements IValueConverter with a Convert method that maps each enum value to a Color
      - Declares the converter in XAML resources with an x:Key
      - Shows the binding syntax with Converter={StaticResource ...}
      - Handles the default/fallback case in the converter
  - name: Diagnose missing BindingContext and non-compiled bindings
    prompt: |
      My .NET MAUI page shows blank labels even though my ViewModel properties
      have values. Here is my XAML:
      ```xml
      <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
                   xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml">
          <VerticalStackLayout>
              <Label Text="{Binding Title}" />
              <Label Text="{Binding Description}" />
          </VerticalStackLayout>
      </ContentPage>
      ```
      What am I doing wrong?
    graders:
      - type: output-matches
        config:
          pattern: (?i)BindingContext
      - type: output-matches
        config:
          pattern: (?i)x:DataType
      - type: prompt
    rubric:
      - Identifies that BindingContext is never set on the page
      - Shows how to set BindingContext either in XAML or code-behind
      - Points out the missing x:DataType and recommends compiled bindings
      - Explains that without BindingContext, bindings resolve to null and display empty