optimize<*>: use custom view locator instead of ContentControl.DataTemplates to avoid memory leak.

src/ViewModels/Launcher.cs

@@ -160,26 +160,23 @@ namespace SourceGit.ViewModels {
                 } else {
                     page = ActivePage;
                     page.Node = node;
-                    page.View = new Views.Repository() { DataContext = repo };
+                    page.Data = repo;
                 }
             } else {
                 page.Node = node;
-                page.View = new Views.Repository() { DataContext = repo };
+                page.Data = repo;
             }
 
             ActivePage = page;
         }
 
         private void CloseRepositoryInTab(LauncherPage page) {
-            if (page.Node.IsRepository) {
+            if (page.Data is Repository repo) {
-                var repo = Preference.FindRepository(page.Node.Id);
+                Commands.AutoFetch.RemoveRepository(repo.FullPath);
-                if (repo != null) {
+                repo.Close();
-                    Commands.AutoFetch.RemoveRepository(repo.FullPath);
-                    repo.Close();
-                }
             }
 
-            page.View = null;
+            page.Data = null;
         }
 
         private LauncherPage _activePage = null;

src/ViewModels/LauncherPage.cs

@@ -8,9 +8,9 @@ namespace SourceGit.ViewModels {
             set => SetProperty(ref _node, value);
         }
 
-        public object View {
+        public object Data {
-            get => _view;
+            get => _data;
-            set => SetProperty(ref _view, value);
+            set => SetProperty(ref _data, value);
         }
 
         public AvaloniaList<Models.Notification> Notifications {
@@ -25,12 +25,12 @@ namespace SourceGit.ViewModels {
                 Bookmark = 0,
                 IsRepository = false,
             };
-            _view = new Views.Welcome() { DataContext = new Welcome() };
+            _data = new Welcome();
         }
 
         public LauncherPage(RepositoryNode node, Repository repo) {
             _node = node;
-            _view = new Views.Repository() { DataContext = repo };
+            _data = repo;
         }
 
         public override string GetId() {
@@ -48,6 +48,6 @@ namespace SourceGit.ViewModels {
         }
 
         private RepositoryNode _node = null;
-        private object _view = null;
+        private object _data = null;
     }
 }

src/Views/Histories.axaml.cs

@@ -1,7 +1,6 @@
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
-using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.VisualTree;
 using System;
@@ -208,11 +207,6 @@ namespace SourceGit.Views {
             InitializeComponent();
         }
 
-        protected override void OnUnloaded(RoutedEventArgs e) {
-            base.OnUnloaded(e);
-            GC.Collect();
-        }
-
         private void OnCommitDataGridLayoutUpdated(object sender, EventArgs e) {
             commitGraph.InvalidateVisual();
         }

src/Views/Launcher.axaml

@@ -223,8 +223,8 @@
       </Border>
     </Grid>
 
-    <!-- Page container -->
+    <!-- Page body -->
-    <ContentControl Grid.Row="1" Background="{DynamicResource Brush.ToolBar}" Content="{Binding ActivePage.View}"/>
+    <v:LauncherBody Grid.Row="1" Background="{DynamicResource Brush.ToolBar}" Data="{Binding ActivePage.Data}"/>
 
     <!-- Popup container -->
     <Grid Grid.Row="1" x:Name="popupContainer" Margin="0,36,0,0" ClipToBounds="True" IsVisible="{Binding ActivePage.Popup, Converter={x:Static ObjectConverters.IsNotNull}}">

src/Views/Launcher.axaml.cs

@@ -23,6 +23,34 @@ namespace SourceGit.Views {
         }
     }
 
+    public class LauncherBody : Border {
+        public static readonly StyledProperty<object> DataProperty =
+            AvaloniaProperty.Register<LauncherBody, object>(nameof(Data), false);
+
+        public object Data {
+            get => GetValue(DataProperty);
+            set => SetValue(DataProperty, value);
+        }
+
+        protected override Type StyleKeyOverride => typeof(Border);
+
+        static LauncherBody() {
+            DataProperty.Changed.AddClassHandler<LauncherBody>((body, ev) => {
+                var data = body.Data;
+                
+                if (data == null) {
+                    body.Child = null;
+                } else if (data is ViewModels.Welcome) {
+                    body.Child = new Welcome { DataContext = data };
+                } else if (data is ViewModels.Repository) {
+                    body.Child = new Repository { DataContext = data };
+                } else {
+                    body.Child = null;
+                }
+            });
+        }
+    }
+
     public partial class Launcher : Window, Models.INotificationReceiver {
         public Launcher() {
             DataContext = new ViewModels.Launcher();

src/Views/Repository.axaml

@@ -447,25 +447,7 @@
           <Button Grid.Column="3" Classes="flat" FontWeight="Regular" Content="{DynamicResource Text.Repository.Abort}" Height="20" Padding="8,0" Margin="4,0" Command="{Binding AbortMerge}"/>
         </Grid>
 
-        <ContentControl Grid.Row="1" Content="{Binding SelectedView}">
+        <v:RepositorySubView Grid.Row="1" Data="{Binding SelectedView}"/>
-          <ContentControl.DataTemplates>
-            <DataTemplate DataType="vm:Histories">
-              <v:Histories/>
-            </DataTemplate>
-
-            <DataTemplate DataType="vm:WorkingCopy">
-              <v:WorkingCopy/>
-            </DataTemplate>
-
-            <DataTemplate DataType="vm:StashesPage">
-              <v:StashesPage/>
-            </DataTemplate>
-
-            <DataTemplate DataType="x:Double">
-              <Border/>
-            </DataTemplate>
-          </ContentControl.DataTemplates>
-        </ContentControl>
       </Grid>
     </Grid>
   </Grid>

src/Views/Repository.axaml.cs

@@ -1,11 +1,45 @@
+using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Primitives;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using SourceGit.ViewModels;
+using System;
 using System.Threading.Tasks;
 
 namespace SourceGit.Views {
+    public class RepositorySubView : Border {
+        public static readonly StyledProperty<object> DataProperty =
+            AvaloniaProperty.Register<RepositorySubView, object>(nameof(Data), false);
+
+        public object Data {
+            get => GetValue(DataProperty);
+            set => SetValue(DataProperty, value);
+        }
+
+        protected override Type StyleKeyOverride => typeof(Border);
+
+        static RepositorySubView() {
+            DataProperty.Changed.AddClassHandler<RepositorySubView>((view, ev) => {
+                var data = view.Data;
+
+                if (data == null) {
+                    view.Child = null;
+                } else if (data is ViewModels.Histories) {
+                    view.Child = new Histories { DataContext = data };
+                } else if (data is ViewModels.WorkingCopy) {
+                    view.Child = new WorkingCopy { DataContext = data };
+                } else if (data is ViewModels.StashesPage) {
+                    view.Child = new StashesPage { DataContext = data };
+                } else {
+                    view.Child = null;
+                }
+
+                GC.Collect();
+            });
+        }
+    }
+
     public partial class Repository : UserControl {
         public Repository() {
             InitializeComponent();

src/Views/StashesPage.axaml.cs

@@ -1,16 +1,9 @@
 using Avalonia.Controls;
-using Avalonia.Interactivity;
-using System;
 
 namespace SourceGit.Views {
     public partial class StashesPage : UserControl {
         public StashesPage() {
             InitializeComponent();
         }
-
-        protected override void OnUnloaded(RoutedEventArgs e) {
-            base.OnUnloaded(e);
-            GC.Collect();
-        }
     }
 }

src/Views/WorkingCopy.axaml.cs

@@ -2,7 +2,6 @@ using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.VisualTree;
-using System;
 using System.Collections.Generic;
 
 namespace SourceGit.Views {
@@ -11,18 +10,6 @@ namespace SourceGit.Views {
             InitializeComponent();
         }
 
-        protected override void OnUnloaded(RoutedEventArgs e) {
-            var vm = DataContext as ViewModels.WorkingCopy;
-            vm.SelectedStagedChange = null;
-            vm.SelectedStagedTreeNode = null;
-            vm.SelectedUnstagedChange = null;
-            vm.SelectedUnstagedTreeNode = null;
-            vm.SetDetail(null, false);
-
-            base.OnUnloaded(e);
-            GC.Collect();
-        }
-
         private void ViewAssumeUnchanged(object sender, RoutedEventArgs e) {
             var repoPage = this.FindAncestorOfType<Repository>();
             if (repoPage != null) {