Move Application.Windows to IClassicDesktopStyleApplicationLifetime

src/Avalonia.Controls/Application.cs

@@ -45,14 +45,6 @@ namespace Avalonia
         private Styles _styles;
         private IResourceDictionary _resources;
 
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Application"/> class.
-        /// </summary>
-        public Application()
-        {
-            Windows = new WindowCollection(this);
-        }
-
         /// <inheritdoc/>
         public event EventHandler<ResourcesChangedEventArgs> ResourcesChanged;
 
@@ -159,14 +151,6 @@ namespace Avalonia
 
         /// <inheritdoc/>
         IResourceNode IResourceNode.ResourceParent => null;
-
-        /// <summary>
-        /// Gets the open windows of the application.
-        /// </summary>
-        /// <value>
-        /// The windows.
-        /// </value>
-        public WindowCollection Windows { get; }
         
         /// <summary>
         /// Application lifetime, use it for things like setting the main window and exiting the app from code

src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs

@@ -1,21 +1,46 @@
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Interactivity;
 
 namespace Avalonia.Controls.ApplicationLifetimes
 {
-    public class ClassicDesktopStyleApplicationLifetime : IClassicDesktopStyleApplicationLifetime
+    public class ClassicDesktopStyleApplicationLifetime : IClassicDesktopStyleApplicationLifetime, IDisposable
     {
         private readonly Application _app;
         private int _exitCode;
         private CancellationTokenSource _cts;
         private bool _isShuttingDown;
+        private HashSet<Window> _windows = new HashSet<Window>();
+
+        private static ClassicDesktopStyleApplicationLifetime _activeLifetime;
+        static ClassicDesktopStyleApplicationLifetime()
+        {
+            Window.WindowOpenedEvent.AddClassHandler(typeof(Window), OnWindowOpened);
+            Window.WindowClosedEvent.AddClassHandler(typeof(Window), WindowClosedEvent);
+        }
+
+        private static void WindowClosedEvent(object sender, RoutedEventArgs e)
+        {
+            _activeLifetime?._windows.Remove((Window)sender);
+            _activeLifetime?.HandleWindowClosed((Window)sender);
+        }
+
+        private static void OnWindowOpened(object sender, RoutedEventArgs e)
+        {
+            _activeLifetime?._windows.Add((Window)sender);
+        }
 
         public ClassicDesktopStyleApplicationLifetime(Application app)
         {
+            if (_activeLifetime != null)
+                throw new InvalidOperationException(
+                    "Can not have multiple active ClassicDesktopStyleApplicationLifetime instances and the previously created one was not disposed");
             _app = app;
-            app.Windows.OnWindowClosed += HandleWindowClosed;
+            _activeLifetime = this;
         }
         
         /// <inheritdoc/>
@@ -29,6 +54,8 @@ namespace Avalonia.Controls.ApplicationLifetimes
         /// <inheritdoc/>
         public Window MainWindow { get; set; }
 
+        public IReadOnlyList<Window> Windows => _windows.ToList();
+
         private void HandleWindowClosed(Window window)
         {
             if (window == null)
@@ -37,7 +64,7 @@ namespace Avalonia.Controls.ApplicationLifetimes
             if (_isShuttingDown)
                 return;
 
-            if (ShutdownMode == ShutdownMode.OnLastWindowClose && _app.Windows.Count == 0)
+            if (ShutdownMode == ShutdownMode.OnLastWindowClose && _windows.Count == 0)
                 Shutdown();
             else if (ShutdownMode == ShutdownMode.OnMainWindowClose && window == MainWindow)
                 Shutdown();
@@ -56,7 +83,8 @@ namespace Avalonia.Controls.ApplicationLifetimes
 
             try
             {
-                _app.Windows.CloseAll();
+                foreach (var w in Windows)
+                    w.Close();
                 var e = new ControlledApplicationLifetimeExitEventArgs(exitCode);
                 Exit?.Invoke(this, e);
                 _exitCode = e.ApplicationExitCode;                
@@ -79,6 +107,12 @@ namespace Avalonia.Controls.ApplicationLifetimes
             Environment.ExitCode = _exitCode;
             return _exitCode;
         }
+
+        public void Dispose()
+        {
+            if (_activeLifetime == this)
+                _activeLifetime = null;
+        }
     }
 }
 

src/Avalonia.Controls/ApplicationLifetimes/IClassicDesktopStyleApplicationLifetime.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 
 namespace Avalonia.Controls.ApplicationLifetimes
 {
@@ -24,5 +25,7 @@ namespace Avalonia.Controls.ApplicationLifetimes
         /// The main window.
         /// </value>
         Window MainWindow { get; set; }
+        
+        IReadOnlyList<Window> Windows { get; }
     }
 }

src/Avalonia.Controls/Window.cs

@@ -14,6 +14,7 @@ using System.Collections.Generic;
 using System.Linq;
 using JetBrains.Annotations;
 using System.ComponentModel;
+using Avalonia.Interactivity;
 
 namespace Avalonia.Controls
 {
@@ -97,6 +98,20 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<bool> CanResizeProperty =
             AvaloniaProperty.Register<Window, bool>(nameof(CanResize), true);
 
+        /// <summary>
+        /// Routed event that can be used for global tracking of window destruction
+        /// </summary>
+        public static readonly RoutedEvent WindowClosedEvent =
+            RoutedEvent.Register<Window, RoutedEventArgs>("WindowClosed", RoutingStrategies.Direct);
+        
+        /// <summary>
+        /// Routed event that can be used for global tracking of opening windows
+        /// </summary>
+        public static readonly RoutedEvent WindowOpenedEvent =
+            RoutedEvent.Register<Window, RoutedEventArgs>("WindowOpened", RoutingStrategies.Direct);
+
+
+
         private readonly NameScope _nameScope = new NameScope();
         private object _dialogResult;
         private readonly Size _maxPlatformClientSize;
@@ -249,26 +264,6 @@ namespace Avalonia.Controls
         /// </summary>
         public event EventHandler<CancelEventArgs> Closing;      
 
-        private static void AddWindow(Window window)
-        {
-            if (Application.Current == null)
-            {
-                return;
-            }
-
-            Application.Current.Windows.Add(window);
-        }
-
-        private static void RemoveWindow(Window window)
-        {
-            if (Application.Current == null)
-            {
-                return;
-            }
-
-            Application.Current.Windows.Remove(window);
-        }
-
         /// <summary>
         /// Closes the window.
         /// </summary>
@@ -376,7 +371,7 @@ namespace Avalonia.Controls
                 return;
             }
 
-            AddWindow(this);
+            this.RaiseEvent(new RoutedEventArgs(WindowOpenedEvent));
 
             EnsureInitialized();
             IsVisible = true;
@@ -438,7 +433,7 @@ namespace Avalonia.Controls
                 throw new InvalidOperationException("The window is already being shown.");
             }
 
-            AddWindow(this);
+            RaiseEvent(new RoutedEventArgs(WindowOpenedEvent));
 
             EnsureInitialized();
             IsVisible = true;
@@ -551,7 +546,7 @@ namespace Avalonia.Controls
 
         protected override void HandleClosed()
         {
-            RemoveWindow(this);
+            RaiseEvent(new RoutedEventArgs(WindowClosedEvent));
 
             base.HandleClosed();
         }

src/Avalonia.Controls/WindowCollection.cs

@@ -1,111 +0,0 @@
-// Copyright (c) The Avalonia Project. All rights reserved.
-// Licensed under the MIT license. See licence.md file in the project root for full license information.
-
-using System;
-using System.Collections;
-using System.Collections.Generic;
-
-using Avalonia.Controls;
-
-namespace Avalonia
-{
-    public class WindowCollection : IReadOnlyList<Window>
-    {
-        private readonly Application _application;
-        private readonly List<Window> _windows = new List<Window>();
-        public event Action<Window> OnWindowClosed;
-
-        public WindowCollection(Application application)
-        {
-            _application = application;
-        }
-
-        /// <inheritdoc />
-        /// <summary>
-        /// Gets the number of elements in the collection.
-        /// </summary>
-        public int Count => _windows.Count;
-
-        /// <inheritdoc />
-        /// <summary>
-        /// Gets the <see cref="T:Avalonia.Controls.Window" /> at the specified index.
-        /// </summary>
-        /// <value>
-        /// The <see cref="T:Avalonia.Controls.Window" />.
-        /// </value>
-        /// <param name="index">The index.</param>
-        /// <returns></returns>
-        public Window this[int index] => _windows[index];
-
-        /// <inheritdoc />
-        /// <summary>
-        /// Returns an enumerator that iterates through the collection.
-        /// </summary>
-        /// <returns>
-        /// An enumerator that can be used to iterate through the collection.
-        /// </returns>
-        public IEnumerator<Window> GetEnumerator()
-        {
-            return _windows.GetEnumerator();
-        }
-
-        /// <inheritdoc />
-        /// <summary>
-        /// Returns an enumerator that iterates through a collection.
-        /// </summary>
-        /// <returns>
-        /// An <see cref="T:System.Collections.IEnumerator"></see> object that can be used to iterate through the collection.
-        /// </returns>
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return GetEnumerator();
-        }
-
-        /// <summary>
-        /// Adds the specified window.
-        /// </summary>
-        /// <param name="window">The window.</param>
-        internal void Add(Window window)
-        {
-            if (window == null)
-            {
-                return;
-            }
-
-            _windows.Add(window);
-        }
-
-        /// <summary>
-        /// Removes the specified window.
-        /// </summary>
-        /// <param name="window">The window.</param>
-        internal void Remove(Window window)
-        {
-            if (window == null)
-            {
-                return;
-            }
-
-            _windows.Remove(window);
-
-            OnRemoveWindow(window);
-        }
-
-        /// <summary>
-        /// Closes all windows and removes them from the underlying collection.
-        /// </summary>
-        public void CloseAll()
-        {
-            while (_windows.Count > 0)
-            {
-                _windows[0].Close(true);
-            }
-        }
-
-        private void OnRemoveWindow(Window window)
-        {
-            if (window != null)
-                OnWindowClosed?.Invoke(window);
-        }
-    }
-}

tests/Avalonia.Controls.UnitTests/DesktopStyleApplicationLifetimeTests.cs

@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
 using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Platform;
 using Avalonia.Threading;
 using Avalonia.UnitTests;
+using Moq;
 using Xunit;
 
 namespace Avalonia.Controls.UnitTests
@@ -14,9 +16,8 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Set_ExitCode_After_Shutdown()
         {
             using (UnitTestApplication.Start(TestServices.MockThreadingInterface))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))    
             {
-                var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current);
-                Dispatcher.UIThread.InvokeAsync(() => lifetime.Shutdown(1337));
                 lifetime.Shutdown(1337);
 
                 var exitCode = lifetime.Start(Array.Empty<string>());
@@ -30,6 +31,7 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Close_All_Remaining_Open_Windows_After_Explicit_Exit_Call()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
             {
                 var windows = new List<Window> { new Window(), new Window(), new Window(), new Window() };
 
@@ -37,9 +39,10 @@ namespace Avalonia.Controls.UnitTests
                 {
                     window.Show();
                 }
-                new ClassicDesktopStyleApplicationLifetime(Application.Current).Shutdown();
+                Assert.Equal(4, lifetime.Windows.Count);
+                lifetime.Shutdown();
 
-                Assert.Empty(Application.Current.Windows);
+                Assert.Empty(lifetime.Windows);
             }
         }
         
@@ -47,8 +50,8 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Only_Exit_On_Explicit_Exit()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
             {
-                var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current);
                 lifetime.ShutdownMode = ShutdownMode.OnExplicitShutdown;
 
                 var hasExit = false;
@@ -81,8 +84,8 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Exit_After_MainWindow_Closed()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
             {
-                var lifetime =  new ClassicDesktopStyleApplicationLifetime(Application.Current);
                 lifetime.ShutdownMode = ShutdownMode.OnMainWindowClose;
 
                 var hasExit = false;
@@ -109,8 +112,8 @@ namespace Avalonia.Controls.UnitTests
         public void Should_Exit_After_Last_Window_Closed()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
             {
-                var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current);
                 lifetime.ShutdownMode = ShutdownMode.OnLastWindowClose;
 
                 var hasExit = false;
@@ -134,6 +137,77 @@ namespace Avalonia.Controls.UnitTests
                 Assert.True(hasExit);
             }
         }
+        
+        [Fact]
+        public void Show_Should_Add_Window_To_OpenWindows()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            {
+                var window = new Window();
+
+                window.Show();
+
+                Assert.Equal(new[] { window }, lifetime.Windows);
+            }
+        }
+
+        [Fact]
+        public void Window_Should_Be_Added_To_OpenWindows_Only_Once()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            {
+                var window = new Window();
+
+                window.Show();
+                window.Show();
+                window.IsVisible = true;
+
+                Assert.Equal(new[] { window }, lifetime.Windows);
+
+                window.Close();
+            }
+        }
+
+        [Fact]
+        public void Close_Should_Remove_Window_From_OpenWindows()
+        {
+            using (UnitTestApplication.Start(TestServices.StyledWindow))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            {
+                var window = new Window();
+
+                window.Show();
+                Assert.Equal(1, lifetime.Windows.Count);
+                window.Close();
+
+                Assert.Empty(lifetime.Windows);
+            }
+        }
+        
+        [Fact]
+        public void Impl_Closing_Should_Remove_Window_From_OpenWindows()
+        {
+            var windowImpl = new Mock<IWindowImpl>();
+            windowImpl.SetupProperty(x => x.Closed);
+            windowImpl.Setup(x => x.Scaling).Returns(1);
+
+            var services = TestServices.StyledWindow.With(
+                windowingPlatform: new MockWindowingPlatform(() => windowImpl.Object));
+
+            using (UnitTestApplication.Start(services))
+            using(var lifetime = new ClassicDesktopStyleApplicationLifetime(Application.Current))
+            {
+                var window = new Window();
+
+                window.Show();
+                Assert.Equal(1, lifetime.Windows.Count);
+                windowImpl.Object.Closed();
+
+                Assert.Empty(lifetime.Windows);
+            }
+        }
     }
     
 }

tests/Avalonia.Controls.UnitTests/WindowTests.cs

@@ -121,75 +121,6 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
-        [Fact]
-        public void Show_Should_Add_Window_To_OpenWindows()
-        {
-            using (UnitTestApplication.Start(TestServices.StyledWindow))
-            {
-                ClearOpenWindows();
-                var window = new Window();
-
-                window.Show();
-
-                Assert.Equal(new[] { window }, Application.Current.Windows);
-            }
-        }
-
-        [Fact]
-        public void Window_Should_Be_Added_To_OpenWindows_Only_Once()
-        {
-            using (UnitTestApplication.Start(TestServices.StyledWindow))
-            {
-                ClearOpenWindows();
-                var window = new Window();
-
-                window.Show();
-                window.Show();
-                window.IsVisible = true;
-
-                Assert.Equal(new[] { window }, Application.Current.Windows);
-
-                window.Close();
-            }
-        }
-
-        [Fact]
-        public void Close_Should_Remove_Window_From_OpenWindows()
-        {
-            using (UnitTestApplication.Start(TestServices.StyledWindow))
-            {
-                ClearOpenWindows();
-                var window = new Window();
-
-                window.Show();
-                window.Close();
-
-                Assert.Empty(Application.Current.Windows);
-            }
-        }
-
-        [Fact]
-        public void Impl_Closing_Should_Remove_Window_From_OpenWindows()
-        {
-            var windowImpl = new Mock<IWindowImpl>();
-            windowImpl.SetupProperty(x => x.Closed);
-            windowImpl.Setup(x => x.Scaling).Returns(1);
-
-            var services = TestServices.StyledWindow.With(
-                windowingPlatform: new MockWindowingPlatform(() => windowImpl.Object));
-
-            using (UnitTestApplication.Start(services))
-            {
-                ClearOpenWindows();
-                var window = new Window();
-
-                window.Show();
-                windowImpl.Object.Closed();
-
-                Assert.Empty(Application.Current.Windows);
-            }
-        }
-
         [Fact]
         public void Closing_Should_Only_Be_Invoked_Once()
         {
@@ -420,12 +351,5 @@ namespace Avalonia.Controls.UnitTests
                 x.Scaling == 1 &&
                 x.CreateRenderer(It.IsAny<IRenderRoot>()) == renderer.Object);
         }
-
-        private void ClearOpenWindows()
-        {
-            // HACK: We really need a decent way to have "statics" that can be scoped to
-            // AvaloniaLocator scopes.
-            Application.Current.Windows.CloseAll();
-        }
     }
 }