Implement CloseRequested in PanePageViewModelBase

Rather than making derved classes implement it if necessary. This is to prevent them maybe forgetting to dispose subscriptions to it.

Author: grokys

src/GitHub.App/ViewModels/GitHubPane/NavigationViewModel.cs

@@ -119,7 +119,7 @@ public int RemoveAll(IPanePageViewModel page)
 
         void BeforeItemAdded(IPanePageViewModel page)
         {
-            if (page.CloseRequested != null && !history.Contains(page))
+            if (!history.Contains(page))
             {
                 page.CloseRequested.Subscribe(_ => RemoveAll(page));
             }

src/GitHub.App/ViewModels/GitHubPane/PanePageViewModelBase.cs

@@ -12,7 +12,8 @@ namespace GitHub.ViewModels.GitHubPane
     public abstract class PanePageViewModelBase : ViewModelBase, IPanePageViewModel, IDisposable
     {
         static readonly Uri paneUri = new Uri("github://pane");
-        Subject<Uri> navigate = new Subject<Uri>();
+        readonly Subject<Uri> navigate = new Subject<Uri>();
+        readonly Subject<Unit> close = new Subject<Unit>();
         Exception error;
         bool isBusy;
         bool isLoading;
@@ -59,7 +60,7 @@ public string Title
         }
 
         /// <inheritdoc/>
-        public virtual IObservable<Unit> CloseRequested { get; }
+        public IObservable<Unit> CloseRequested => close;
 
         /// <inheritdoc/>
         public IObservable<Uri> NavigationRequested => navigate;
@@ -84,6 +85,11 @@ public void Dispose()
         /// <inheritdoc/>
         public virtual Task Refresh() => Task.CompletedTask;
 
+        /// <summary>
+        /// Sends a request to close the page.
+        /// </summary>
+        protected void Close() => close.OnNext(Unit.Default);
+
         /// <summary>
         /// Sends a request to navigate to a new page.
         /// </summary>
@@ -96,8 +102,8 @@ protected virtual void Dispose(bool disposing)
         {
             if (disposing)
             {
-                navigate?.Dispose();
-                navigate = null;
+                close.Dispose();
+                navigate.Dispose();
             }
         }
     }

src/GitHub.App/ViewModels/GitHubPane/PullRequestCreationViewModel.cs

@@ -95,6 +95,7 @@ public PullRequestCreationViewModel(
             });
 
             Cancel = ReactiveCommand.Create();
+            Cancel.Subscribe(_ => Close());
 
             isExecuting = CreatePullRequest.IsExecuting.ToProperty(this, x => x.IsExecuting);
 
@@ -298,7 +299,5 @@ ReactivePropertyValidator BranchValidator
             get { return branchValidator; }
             set { this.RaiseAndSetIfChanged(ref branchValidator, value); }
         }
-
-        public override IObservable<Unit> CloseRequested => Cancel.SelectUnit();
     }
 }

test/UnitTests/GitHub.App/ViewModels/GitHubPane/NavigationViewModelTests.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Reactive;
+using System.Reactive.Linq;
 using System.Reactive.Subjects;
 using GitHub.ViewModels.GitHubPane;
 using NSubstitute;
@@ -412,7 +413,7 @@ public void CallsDeactivatedAndThenDisposedOnPages()
     static IPanePageViewModel CreatePage()
     {
         var result = Substitute.For<IPanePageViewModel>();
-        result.CloseRequested.Returns((IObservable<Unit>)null);
+        result.CloseRequested.Returns(Observable.Never<Unit>());
         return result;
     }
 }