Merge branch 'issue-284'

src/Markup/Perspex.Markup.Xaml/Templates/TreeDataTemplate.cs

@@ -36,12 +36,12 @@ namespace Perspex.Markup.Xaml.Templates
             }
         }
 
-        public IEnumerable ItemsSelector(object item)
+        public InstancedBinding ItemsSelector(object item)
         {
             if (ItemsSource != null)
             {
                 var obs = new ExpressionObserver(item, ItemsSource.Path);
-                return obs.Take(1).Wait() as IEnumerable;
+                return new InstancedBinding(obs);
             }
 
             return null;

src/Perspex.Base/PerspexObject.cs

@@ -25,6 +25,17 @@ namespace Perspex
     /// </remarks>
     public class PerspexObject : IPerspexObject, IPerspexObjectDebug, INotifyPropertyChanged
     {
+        /// <summary>
+        /// Maintains a list of direct property binding subscriptions so that the binding source
+        /// doesn't get collected.
+        /// </summary>
+        /// <remarks>
+        /// If/when we provide a ClearBindings() method, then this collection will be need to be
+        /// moved to an instance field and indexed by property, but until that point a static
+        /// collection will suffice.
+        /// </remarks>
+        private static List<IDisposable> s_directBindings = new List<IDisposable>();
+
         /// <summary>
         /// The parent object that inherited values are inherited from.
         /// </summary>
@@ -401,9 +412,20 @@ namespace Perspex
                     property,
                     GetDescription(source));
 
-                return source
+                IDisposable subscription = null;
+
+                subscription = source
                     .Select(x => TypeUtilities.CastOrDefault(x, property.PropertyType))
+                    .Do(_ => { }, () => s_directBindings.Remove(subscription))
                     .Subscribe(x => SetValue(property, x));
+
+                s_directBindings.Add(subscription);
+
+                return Disposable.Create(() =>
+                {
+                    subscription.Dispose();
+                    s_directBindings.Remove(subscription);
+                });
             }
             else
             {

src/Perspex.Controls/Generators/TreeItemContainerGenerator.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using Perspex.Controls.Templates;
+using Perspex.Data;
 
 namespace Perspex.Controls.Generators
 {
@@ -76,7 +77,7 @@ namespace Perspex.Controls.Generators
                 var result = new T();
 
                 result.SetValue(ContentProperty, template.Build(item));
-                result.SetValue(ItemsProperty, template.ItemsSelector(item));
+                BindingOperations.Apply(result, ItemsProperty, template.ItemsSelector(item), null);
 
                 if (!(item is IControl))
                 {

src/Perspex.Controls/Templates/FuncTreeDataTemplate.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections;
 using System.Reflection;
+using Perspex.Data;
 
 namespace Perspex.Controls.Templates
 {
@@ -59,9 +60,9 @@ namespace Perspex.Controls.Templates
         /// </summary>
         /// <param name="item">The item.</param>
         /// <returns>The child items, or null if no child items.</returns>
-        public IEnumerable ItemsSelector(object item)
+        public InstancedBinding ItemsSelector(object item)
         {
-            return this?._itemsSelector(item);
+            return new InstancedBinding(this?._itemsSelector(item));
         }
 
         /// <summary>

src/Perspex.Controls/Templates/ITreeDataTemplate.cs

@@ -1,7 +1,7 @@
 // Copyright (c) The Perspex Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
-using System.Collections;
+using Perspex.Data;
 
 namespace Perspex.Controls.Templates
 {
@@ -14,7 +14,10 @@ namespace Perspex.Controls.Templates
         /// Selects the child items of an item.
         /// </summary>
         /// <param name="item">The item.</param>
-        /// <returns>The child items, or null if no child items.</returns>
-        IEnumerable ItemsSelector(object item);
+        /// <returns>
+        /// An <see cref="InstancedBinding"/> holding the items, or an observable that tracks the
+        /// items. May return null if no child items.
+        /// </returns>
+        InstancedBinding ItemsSelector(object item);
     }
 }

tests/Perspex.Base.UnitTests/PerspexObjectTests_Direct.cs

@@ -333,6 +333,50 @@ namespace Perspex.Base.UnitTests
             Assert.Equal("second", target.Foo);
         }
 
+        [Fact]
+        public void Binding_To_Direct_Property_Does_Not_Get_Collected()
+        {
+            var target = new Class2();
+
+            Func<WeakReference> setupBinding = () =>
+            {
+                var source = new Subject<string>();
+                var sub = target.Bind((PerspexProperty)Class1.FooProperty, source);
+                return new WeakReference(source);
+            };
+
+            var weakSource = setupBinding();
+
+            GC.Collect();
+
+            Assert.True(weakSource.IsAlive);
+        }
+
+        [Fact]
+        public void Binding_To_Direct_Property_Gets_Collected_When_Completed()
+        {
+            var target = new Class2();
+
+            Func<WeakReference> setupBinding = () =>
+            {
+                var source = new Subject<string>();
+                var sub = target.Bind((PerspexProperty)Class1.FooProperty, source);
+                return new WeakReference(source);
+            };
+        
+            var weakSource = setupBinding();
+
+            Action completeSource = () =>
+            {
+                ((ISubject<string>)weakSource.Target).OnCompleted();
+            };
+
+            completeSource();
+            GC.Collect();
+
+            Assert.False(weakSource.IsAlive);
+        }
+
         [Fact]
         public void Property_Notifies_Initialized()
         {

tests/Perspex.Controls.UnitTests/Perspex.Controls.UnitTests.csproj

@@ -148,6 +148,10 @@
       <Project>{3e53a01a-b331-47f3-b828-4a5717e77a24}</Project>
       <Name>Perspex.Markup.Xaml</Name>
     </ProjectReference>
+    <ProjectReference Include="..\..\src\Markup\Perspex.Markup\Perspex.Markup.csproj">
+      <Project>{6417e941-21bc-467b-a771-0de389353ce6}</Project>
+      <Name>Perspex.Markup</Name>
+    </ProjectReference>
     <ProjectReference Include="..\..\src\Perspex.Animation\Perspex.Animation.csproj">
       <Project>{D211E587-D8BC-45B9-95A4-F297C8FA5200}</Project>
       <Name>Perspex.Animation</Name>

tests/Perspex.Controls.UnitTests/TreeViewTests.cs

@@ -1,13 +1,16 @@
 // Copyright (c) The Perspex 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.Generic;
 using System.Linq;
 using Perspex.Collections;
 using Perspex.Controls.Presenters;
 using Perspex.Controls.Templates;
+using Perspex.Data;
 using Perspex.Input;
 using Perspex.LogicalTree;
+using Perspex.Markup.Data;
 using Perspex.UnitTests;
 using Xunit;
 
@@ -252,6 +255,39 @@ namespace Perspex.Controls.UnitTests
             Assert.NotNull(NameScope.GetNameScope((TreeViewItem)item));
         }
 
+        [Fact]
+        public void Should_React_To_Children_Changing()
+        {
+            var data = CreateTestTreeData();
+
+            var target = new TreeView
+            {
+                Template = CreateTreeViewTemplate(),
+                Items = data,
+                DataTemplates = CreateNodeDataTemplate(),
+            };
+
+            ApplyTemplates(target);
+
+            Assert.Equal(new[] { "Root" }, ExtractItemHeader(target, 0));
+            Assert.Equal(new[] { "Child1", "Child2" }, ExtractItemHeader(target, 1));
+            Assert.Equal(new[] { "Grandchild2a" }, ExtractItemHeader(target, 2));
+
+            // Make sure that the binding to Node.Children does not get collected.
+            GC.Collect();
+
+            data[0].Children = new PerspexList<Node>
+            {
+                new Node
+                {
+                    Value = "NewChild1",
+                }
+            };
+
+            Assert.Equal(new[] { "Root" }, ExtractItemHeader(target, 0));
+            Assert.Equal(new[] { "NewChild1" }, ExtractItemHeader(target, 1));
+        }
+
         private void ApplyTemplates(TreeView tree)
         {
             tree.ApplyTemplate();
@@ -303,9 +339,7 @@ namespace Perspex.Controls.UnitTests
         {
             return new DataTemplates
             {
-                new FuncTreeDataTemplate<Node>(
-                    x => new TextBlock { Text = x.Value },
-                    x => x.Children),
+                new TestTreeDataTemplate()
             };
         }
 
@@ -360,10 +394,45 @@ namespace Perspex.Controls.UnitTests
             }
         }
 
-        private class Node
+        private class Node :  NotifyingBase
         {
+            private IPerspexList<Node> _children;
+
             public string Value { get; set; }
-            public IPerspexList<Node> Children { get; set; }
+
+            public IPerspexList<Node> Children
+            {
+                get
+                {
+                    return _children;
+                }
+
+                set
+                {
+                    _children = value;
+                    RaisePropertyChanged(nameof(Children));
+                }
+            }
+        }
+
+        private class TestTreeDataTemplate : ITreeDataTemplate
+        {
+            public IControl Build(object param)
+            {
+                var node = (Node)param;
+                return new TextBlock { Text = node.Value };
+            }
+
+            public InstancedBinding ItemsSelector(object item)
+            {
+                var obs = new ExpressionObserver(item, nameof(Node.Children));
+                return new InstancedBinding(obs);
+            }
+
+            public bool Match(object data)
+            {
+                return data is Node;
+            }
         }
     }
 }

tests/Perspex.Markup.UnitTests/Data/ExpressionObserverTests_Indexer.cs

@@ -8,6 +8,7 @@ using System.Reactive.Linq;
 using Perspex.Collections;
 using Perspex.Diagnostics;
 using Perspex.Markup.Data;
+using Perspex.UnitTests;
 using Xunit;
 
 namespace Perspex.Markup.UnitTests.Data

tests/Perspex.Markup.UnitTests/Data/ExpressionObserverTests_Observable.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
 using Perspex.Markup.Data;
+using Perspex.UnitTests;
 using Xunit;
 
 namespace Perspex.Markup.UnitTests.Data

tests/Perspex.Markup.UnitTests/Data/ExpressionObserverTests_Property.cs

@@ -8,6 +8,7 @@ using System.Reactive.Linq;
 using System.Reactive.Subjects;
 using Microsoft.Reactive.Testing;
 using Perspex.Markup.Data;
+using Perspex.UnitTests;
 using Xunit;
 
 namespace Perspex.Markup.UnitTests.Data
@@ -385,11 +386,6 @@ namespace Perspex.Markup.UnitTests.Data
                     RaisePropertyChanged(nameof(Next));
                 }
             }
-
-            public void RaisePropertyChanged(string propertyName)
-            {
-                base.RaisePropertyChanged(propertyName);
-            }
         }
 
         private class Class2 : NotifyingBase, INext

tests/Perspex.Markup.UnitTests/Data/ExpressionObserverTests_SetValue.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Reactive.Linq;
 using Perspex.Markup.Data;
+using Perspex.UnitTests;
 using Xunit;
 
 namespace Perspex.Markup.UnitTests.Data

tests/Perspex.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs

@@ -7,6 +7,7 @@ using System.Reactive.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Perspex.Markup.Data;
+using Perspex.UnitTests;
 using Xunit;
 
 namespace Perspex.Markup.UnitTests.Data

tests/Perspex.Markup.UnitTests/Perspex.Markup.UnitTests.csproj

@@ -96,7 +96,6 @@
     <Compile Include="Data\ExpressionObserverTests_SetValue.cs" />
     <Compile Include="Data\ExpressionObserverTests_Task.cs" />
     <Compile Include="Data\ExpressionSubjectTests.cs" />
-    <Compile Include="Data\NotifyingBase.cs" />
     <Compile Include="DefaultValueConverterTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="UnitTestSynchronizationContext.cs" />

tests/Perspex.Markup.UnitTests/Data/NotifyingBase.cs → tests/Perspex.UnitTests/NotifyingBase.cs

@@ -4,7 +4,7 @@
 using System.ComponentModel;
 using System.Linq;
 
-namespace Perspex.Markup.UnitTests.Data
+namespace Perspex.UnitTests
 {
     public class NotifyingBase : INotifyPropertyChanged
     {
@@ -34,7 +34,7 @@ namespace Perspex.Markup.UnitTests.Data
             private set;
         }
 
-        protected void RaisePropertyChanged(string propertyName)
+        public void RaisePropertyChanged(string propertyName)
         {
             _propertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
         }

tests/Perspex.UnitTests/Perspex.UnitTests.csproj

@@ -62,6 +62,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="NotifyingBase.cs" />
     <Compile Include="TestTemplatedRoot.cs" />
     <Compile Include="TestRoot.cs" />
     <Compile Include="TestServices.cs" />