Open changed file when double clicked.

Only very basic implementation: file is always opened irrespective of
what the `OpenChangedFileAction` is and whether the local file is
up-to-date. This needs fleshing out.

Author: grokys

src/GitHub.App/SampleData/PullRequestDetailViewModelDesigner.cs

@@ -73,7 +73,9 @@ public PullRequestDetailViewModelDesigner()
 
         public ReactiveCommand<Unit> Checkout { get; }
         public ReactiveCommand<object> OpenOnGitHub { get; }
+        public ReactiveCommand<object> OpenFile { get; }
         public ReactiveCommand<object> ToggleChangedFilesView { get; }
         public ReactiveCommand<object> ToggleOpenChangedFileAction { get; }
+        public ReactiveCommand<object> ViewOpenFile { get; }
     }
 }

src/GitHub.App/ViewModels/PullRequestDetailViewModel.cs

@@ -97,6 +97,8 @@ public PullRequestDetailViewModel(
             Checkout = ReactiveCommand.CreateAsyncObservable(canCheckout, DoCheckout);
 
             OpenOnGitHub = ReactiveCommand.Create();
+            OpenFile = ReactiveCommand.Create();
+            OpenFile.Subscribe(x => DoOpenFile((IPullRequestFileViewModel)x));
 
             ToggleChangedFilesView = ReactiveCommand.Create();
             ToggleChangedFilesView.Subscribe(_ =>
@@ -111,6 +113,8 @@ public PullRequestDetailViewModel(
                 OpenChangedFileAction = OpenChangedFileAction == OpenChangedFileAction.Diff ?
                     OpenChangedFileAction.Open : OpenChangedFileAction.Diff;
             });
+
+            ViewOpenFile = ReactiveCommand.Create();
         }
 
         /// <summary>
@@ -269,6 +273,16 @@ public string CheckoutDisabledMessage
         /// </summary>
         public ReactiveCommand<object> OpenOnGitHub { get; }
 
+        /// <summary>
+        /// Gets a command that opens the specified file according to <see cref="ChangedFilesView"/>.
+        /// </summary>
+        /// <remarks>
+        /// An <see cref="IPullRequestFileViewModel"/> should be passed as the parameter to this command's
+        /// Execute method. It triggers <see cref="ViewOpenFile"/> or <see cref="ViewCompareFiles"/> which
+        /// should be handled by the view to implement opening or comparing the file.
+        /// </remarks>
+        public ReactiveCommand<object> OpenFile { get; }
+
         /// <summary>
         /// Gets a command that toggles the <see cref="ChangedFilesView"/> property.
         /// </summary>
@@ -279,6 +293,14 @@ public string CheckoutDisabledMessage
         /// </summary>
         public ReactiveCommand<object> ToggleOpenChangedFileAction { get; }
 
+        /// <summary>
+        /// Gets a command that informs the view that the specified file should be opened.
+        /// </summary>
+        /// <remarks>
+        /// The parameter passed is a string detailing the full path to the file.
+        /// </remarks>
+        public ReactiveCommand<object> ViewOpenFile { get; }
+
         /// <summary>
         /// Initializes the view model with new data.
         /// </summary>
@@ -491,5 +513,12 @@ IObservable<Unit> DoCheckout(object unused)
                 return Observable.Empty<Unit>();
             });
         }
+
+        void DoOpenFile(IPullRequestFileViewModel x)
+        {
+            // TODO: Handle diffing files accoring to OpenChangedFileAction and getting a file from another branch etc.
+            var fullPath = Path.Combine(repository.LocalPath, x.Path, x.FileName);
+            ViewOpenFile.Execute(fullPath);
+        }
     }
 }

src/GitHub.Exports.Reactive/ViewModels/IPullRequestDetailViewModel.cs

@@ -176,6 +176,16 @@ public interface IPullRequestDetailViewModel : IViewModel, IHasBusy
         /// </summary>
         ReactiveCommand<object> OpenOnGitHub { get; }
 
+        /// <summary>
+        /// Gets a command that opens the specified file according to <see cref="ChangedFilesView"/>.
+        /// </summary>
+        /// <remarks>
+        /// An <see cref="IPullRequestFileViewModel"/> should be passed as the parameter to this command's
+        /// Execute method. It triggers <see cref="ViewOpenFile"/> or <see cref="ViewCompareFiles"/> which
+        /// should be handled by the view to implement opening or comparing the file.
+        /// </remarks>
+        ReactiveCommand<object> OpenFile { get; }
+
         /// <summary>
         /// Gets a command that toggles the <see cref="ChangedFilesView"/> property.
         /// </summary>
@@ -185,5 +195,13 @@ public interface IPullRequestDetailViewModel : IViewModel, IHasBusy
         /// Gets a command that toggles the <see cref="OpenChangedFileAction"/> property.
         /// </summary>
         ReactiveCommand<object> ToggleOpenChangedFileAction { get; }
+
+        /// <summary>
+        /// Gets a command that informs the view that the specified file should be opened.
+        /// </summary>
+        /// <remarks>
+        /// The parameter passed is a string detailing the full path to the file.
+        /// </remarks>
+        ReactiveCommand<object> ViewOpenFile { get; }
     }
 }

src/GitHub.VisualStudio/UI/Views/PullRequestDetailView.xaml

@@ -13,7 +13,7 @@
                                     Background="{DynamicResource GitHubVsToolWindowBackground}"
                                     DataContext="{Binding ViewModel}"
                                     d:DesignWidth="356"
-                                    d:DesignHeight="640"
+                                    d:DesignHeight="780"
                                     mc:Ignorable="d"
                                     Style="{DynamicResource BusyStateView}">
     <d:DesignProperties.DataContext>
@@ -400,7 +400,8 @@
                             <TreeView ItemsSource="{Binding ChangedFilesTree}" 
                                       Background="Transparent"
                                       BorderThickness="0"
-                                      Margin="0 6 0 0">
+                                      Margin="0 6 0 0"
+                                      MouseDoubleClick="FileListMouseDoubleClick">
                                 <TreeView.Style>
                                     <Style TargetType="TreeView">
                                         <Style.Triggers>
@@ -422,13 +423,13 @@
                                         <StackPanel Orientation="Horizontal">
                                             <!-- TODO: Use the right icon here -->
                                             <ui:OcticonImage Icon="briefcase" Foreground="{DynamicResource GitHubVsWindowText}"/>
-                                            <TextBlock Text="{Binding DirectoryName}" Margin="4 0" VerticalAlignment="Center"/>
+                                            <TextBlock Text="{Binding DirectoryName}" Margin="4 2" VerticalAlignment="Center"/>
                                         </StackPanel>
                                     </HierarchicalDataTemplate>
                                     <DataTemplate DataType="{x:Type vm:PullRequestFileViewModel}">
                                         <StackPanel Orientation="Horizontal">
                                             <ui:OcticonImage Icon="file_code" Foreground="{DynamicResource GitHubVsWindowText}"/>
-                                            <TextBlock Text="{Binding FileName}" Margin="4 0" VerticalAlignment="Center"/>
+                                            <TextBlock Text="{Binding FileName}" Margin="4 2" VerticalAlignment="Center"/>
                                         </StackPanel>
                                     </DataTemplate>
                                 </TreeView.Resources>
@@ -438,7 +439,8 @@
                             <ListView ItemsSource="{Binding ChangedFilesList}"
                                       Background="Transparent"
                                       BorderThickness="0"
-                                      Margin="0 6 0 0" >
+                                      Margin="0 6 0 0"
+                                      MouseDoubleClick="FileListMouseDoubleClick">
                                 <ListView.Style>
                                     <Style TargetType="ListView">
                                         <Style.Triggers>

src/GitHub.VisualStudio/UI/Views/PullRequestDetailView.xaml.cs

@@ -40,6 +40,7 @@ public PullRequestDetailView()
             this.WhenActivated(d =>
             {
                 d(ViewModel.OpenOnGitHub.Subscribe(_ => DoOpenOnGitHub()));
+                d(ViewModel.ViewOpenFile.Subscribe(x => DoOpenFile((string)x)));
             });
 
             OpenChangesOptionsMenu = ReactiveCommand.Create();
@@ -109,5 +110,20 @@ void DoOpenChangesOptionsMenu(dynamic o)
             menu.VerticalOffset = o.MenuY;
             menu.IsOpen = true;
         }
+
+        void DoOpenFile(string fileName)
+        {
+            Services.Dte.ItemOperations.OpenFile(fileName);
+        }
+
+        private void FileListMouseDoubleClick(object sender, MouseButtonEventArgs e)
+        {
+            var file = (e.OriginalSource as FrameworkElement)?.DataContext as IPullRequestFileViewModel;
+
+            if (file != null)
+            {
+                ViewModel.OpenFile.Execute(file);
+            }
+        }
     }
 }