Merge pull request #3239 from chowarth/feature/containerprovider

Add ContainerProvider for resolving dependencies in XAML

Author: dansiegel

src/Maui/Prism.Maui/Ioc/ContainerProvider.cs

@@ -0,0 +1,67 @@
+#nullable enable
+namespace Prism.IoC;
+
+/// <summary>
+/// Provides Types and Services registered with the Container
+/// </summary>
+/// <typeparam name="T">The type to Resolve</typeparam>
+/// <example>
+/// We can use this to build better types such as ValueConverters with full dependency injection
+/// <code>
+/// public class MyValueConverter : IValueConverter
+/// {
+///     private readonly ILogger _logger { get; }
+///     
+///     public MyValueConverter(ILogger logger)
+///     {
+///         _logger = logger;
+///     }
+///
+///     public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+///     {
+///         _logger.Log($"Converting {value.GetType().Name} to {targetType.Name}", Category.Debug, Priority.None);
+///         // do stuff
+///     }
+///
+///     public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+///     {
+///         _logger.Log($"Converting back from {value.GetType().Name} to {targetType.Name}", Category.Debug, Priority.None);
+///         return null;
+///     }
+/// }
+/// </code>
+/// We can then simply use our ValueConverter or other class directly in XAML
+/// <![CDATA[
+/// <ContentPage xmlns:prism="clr-namespace:Prism.Ioc;assembly=Prism.Maui">
+///     <ContentPage.Resources>
+///         <ResourceDictionary>
+///             <prism:ContainerProvider x:TypeArguments="MyValueConverter" x:Key="myValueConverter" />
+///         <ResourceDictionary>
+///     <ContentPage.Resources>
+///     <Label Text="{Binding SomeProp, Converter={StaticResource myValueConverter}}" />
+/// </ContentPage>
+/// ]]>
+/// </example>
+public class ContainerProvider<T>
+{
+    /// <summary>
+    /// The Name used to register the type with the Container
+    /// </summary>
+    public string? Name { get; set; }
+
+    /// <summary>
+    /// Resolves the specified type from the Application's Container
+    /// </summary>
+    /// <param name="containerProvider"></param>
+    public static implicit operator T(ContainerProvider<T> containerProvider)
+    {
+        var container = ContainerLocator.Container;
+        if (container == null) return default(T);
+        if (string.IsNullOrWhiteSpace(containerProvider.Name))
+        {
+            return container.Resolve<T>();
+        }
+
+        return container.Resolve<T>(containerProvider.Name);
+    }
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Fixtures/IoC/ContainerProviderTests.cs

@@ -0,0 +1,76 @@
+using Prism.DryIoc.Maui.Tests.Mocks;
+using Prism.DryIoc.Maui.Tests.Mocks.Events;
+using Prism.DryIoc.Maui.Tests.Mocks.ViewModels;
+using Prism.DryIoc.Maui.Tests.Mocks.Views;
+using Prism.Events;
+using Prism.IoC;
+
+namespace Prism.DryIoc.Maui.Tests.Fixtures.IoC;
+
+public class ContainerProviderTests(ITestOutputHelper testOutputHelper) : TestBase(testOutputHelper)
+{
+    [Fact]
+    public void CanResolveUnamedType()
+    {
+        var builder = CreateBuilder(prism => { });
+        var app = builder.Build();
+        var containerProvider = new ContainerProvider<ConcreteTypeMock>();
+
+        ConcreteTypeMock type = (ConcreteTypeMock)containerProvider;
+
+        Assert.NotNull(type);
+        Assert.IsType<ConcreteTypeMock>(type);
+    }
+
+    [Fact]
+    public void CanResolvedNamedType()
+    {
+        var builder = CreateBuilder(prism => { });
+        var app = builder.Build();
+        var containerProvider = new ContainerProvider<ConcreteTypeMock>
+        {
+            Name = ConcreteTypeMock.Key
+        };
+
+        ConcreteTypeMock vm = (ConcreteTypeMock)containerProvider;
+
+        Assert.NotNull(vm);
+        Assert.IsType<ConcreteTypeMock>(vm);
+    }
+
+    [Fact]
+    public async Task ProvidesValueFromResourceDictionary()
+    {
+        var builder = CreateBuilder(prism =>
+        {
+            prism.RegisterTypes(containerRegistry =>
+            {
+                containerRegistry.RegisterForNavigation<MockXamlView, MockXamlViewViewModel>();
+            })
+            .CreateWindow(n =>
+                n.CreateBuilder()
+                .AddSegment<MockViewAViewModel>()
+                .NavigateAsync());
+        });
+        var app = builder.Build();
+
+        var ea = app.Services.GetService<IEventAggregator>();
+        var events = new List<string>();
+        ea.GetEvent<TestActionEvent>().Subscribe((m) => events.Add(m));
+
+        var navigation = app.Services.GetService<INavigationService>();
+        await navigation.CreateBuilder()
+            .AddSegment<MockXamlViewViewModel>()
+            .NavigateAsync();
+
+        Assert.Contains(events, e => e == "Convert");
+        var window = GetWindow(app);
+        Assert.NotNull(window.Page);
+
+        var xamlView = window.Page as MockXamlView;
+        var viewModel = xamlView.BindingContext as MockXamlViewViewModel;
+
+        xamlView.TestEntry.Text = "Foo Bar";
+        Assert.Contains(events, e => e == "ConvertBack");
+    }
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/ConcreteTypeMock.cs

@@ -0,0 +1,6 @@
+namespace Prism.DryIoc.Maui.Tests.Mocks;
+
+internal class ConcreteTypeMock
+{
+    public const string Key = "ConcreteTypeMock";
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Converters/MockValueConverter.cs

@@ -0,0 +1,27 @@
+using System.Globalization;
+using Prism.DryIoc.Maui.Tests.Mocks.Events;
+using Prism.Events;
+
+namespace Prism.DryIoc.Maui.Tests.Mocks.Converters;
+
+internal class MockValueConverter : IValueConverter
+{
+    private IEventAggregator _eventAggreator { get; }
+
+    public MockValueConverter(IEventAggregator eventAggreator)
+    {
+        _eventAggreator = eventAggreator;
+    }
+
+    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+    {
+        _eventAggreator.GetEvent<TestActionEvent>().Publish("Convert");
+        return value;
+    }
+
+    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+    {
+        _eventAggreator.GetEvent<TestActionEvent>().Publish("ConvertBack");
+        return value;
+    }
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Events/TestActionEvent.cs

@@ -0,0 +1,7 @@
+using Prism.Events;
+
+namespace Prism.DryIoc.Maui.Tests.Mocks.Events;
+
+internal class TestActionEvent : PubSubEvent<string>
+{
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/ViewModels/MockXamlViewViewModel.cs

@@ -0,0 +1,11 @@
+namespace Prism.DryIoc.Maui.Tests.Mocks.ViewModels;
+
+internal class MockXamlViewViewModel : BindableBase
+{
+    private string _test = "Initial Value";
+    public string Test
+    {
+        get => _test;
+        set => SetProperty(ref _test, value);
+    }
+}

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Views/MockXamlView.xaml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:prism="clr-namespace:Prism.IoC;assembly=Prism.Maui"
+    xmlns:converters="clr-namespace:Prism.DryIoc.Maui.Tests.Mocks.Converters"
+    x:Class="Prism.DryIoc.Maui.Tests.Mocks.Views.MockXamlView"
+    Title="MockXamlView">
+  
+    <ContentPage.Resources>
+        <ResourceDictionary>
+        <prism:ContainerProvider
+            x:TypeArguments="converters:MockValueConverter"
+            x:Key="mockValueConverter" />
+        </ResourceDictionary>
+    </ContentPage.Resources>
+  
+    <StackLayout>
+        <Entry x:Name="testEntry"
+            Text="{Binding Test,Converter={StaticResource mockValueConverter}}" />
+    </StackLayout>
+  
+</ContentPage>

tests/Maui/Prism.DryIoc.Maui.Tests/Mocks/Views/MockXamlView.xaml.cs

@@ -0,0 +1,12 @@
+namespace Prism.DryIoc.Maui.Tests.Mocks.Views;
+
+[XamlCompilation(XamlCompilationOptions.Compile)]
+public partial class MockXamlView : ContentPage
+{
+	public MockXamlView()
+	{
+		InitializeComponent();
+	}
+
+    public Entry TestEntry => testEntry;
+}