fix selected item

part of #412

Wox/MainWindow.xaml

@@ -41,8 +41,8 @@
                   Style="{DynamicResource PendingLineStyle}" Visibility="{Binding ProgressBarVisibility, Mode=TwoWay}" 
                   Y1="0" Y2="0" X2="100" Height="2" Width="752" StrokeThickness="1">
             </Line>
-            <ContentControl Content="{Binding Results}" Visibility="{Binding ResultListBoxVisibility}" />
+            <ContentControl Name="Results" Content="{Binding Results}" Visibility="{Binding ResultListBoxVisibility}" />
-            <ContentControl Content="{Binding ContextMenu}" Visibility="{Binding ContextMenuVisibility}" />
+            <ContentControl Name ="ContextMenu" Content="{Binding ContextMenu}" Visibility="{Binding ContextMenuVisibility}" />
         </StackPanel>
     </Border>
 </Window>

Wox/MainWindow.xaml.cs

@@ -333,15 +333,6 @@ namespace Wox
                     var vm = DataContext as MainViewModel;
                     if (vm != null)
                     {
-                        if (vm.ContextMenuVisibility.IsVisible())
-                        {
-                            vm.ContextMenu.SelectResult(result);
-                        }
-                        else
-                        {
-                            vm.Results.SelectResult(result);
-                        }
-
                         if (e.ChangedButton == MouseButton.Left)
                         {
                             vm.OpenResultCommand.Execute(null);

Wox/ResultListBox.xaml

@@ -7,11 +7,16 @@
          xmlns:vm="clr-namespace:Wox.ViewModel"
          mc:Ignorable="d" d:DesignWidth="100" d:DesignHeight="100"
          d:DataContext="{d:DesignInstance vm:ResultsViewModel}"
-         MaxHeight="{Binding MaxHeight}" SelectedItem="{Binding SelectedResult}"
+         MaxHeight="{Binding MaxHeight}" 
+         SelectedIndex="{Binding SelectedIndex, Mode=TwoWay}"
+         SelectedItem="{Binding SelectedItem, Mode=OneWayToSource}" 
          HorizontalContentAlignment="Stretch" ItemsSource="{Binding Results}" Margin="{Binding Margin}"
-         Style="{DynamicResource BaseListboxStyle}" SelectionChanged="lbResults_SelectionChanged" Focusable="False"
+         Style="{DynamicResource BaseListboxStyle}"  Focusable="False"
          KeyboardNavigation.DirectionalNavigation="Cycle" SelectionMode="Single"
-         VirtualizingStackPanel.IsVirtualizing="True" VirtualizingStackPanel.VirtualizationMode="Standard">
+         VirtualizingStackPanel.IsVirtualizing="True" VirtualizingStackPanel.VirtualizationMode="Standard"
+         SelectionChanged="OnSelectionChanged"
+         IsSynchronizedWithCurrentItem="True">
+    <!--IsSynchronizedWithCurrentItem: http://stackoverflow.com/a/7833798/2833083-->
     <ListBox.ItemTemplate>
         <DataTemplate>
             <DataTemplate.DataType>
@@ -65,6 +70,7 @@
     <!--http://stackoverflow.com/questions/16819577/setting-background-color-or-wpf-4-0-listbox-windows-8/#16820062-->
     <ListBox.ItemContainerStyle>
         <Style TargetType="{x:Type ListBoxItem}">
+            <EventSetter Event="MouseEnter" Handler="OnMouseEnter"></EventSetter>
             <Setter Property="Height" Value="50" />
             <Setter Property="Margin" Value="0" />
             <Setter Property="Padding" Value="0"/>

Wox/ResultListBox.xaml.cs

@@ -3,6 +3,7 @@ using System.Linq;
 using System.Runtime.Remoting.Contexts;
 using System.Windows;
 using System.Windows.Controls;
+using System.Windows.Input;
 using Wox.Plugin;
 using Wox.ViewModel;
 
@@ -13,10 +14,10 @@ namespace Wox
     {
         public void AddResults(List<Result> newRawResults)
         {
-            var vm = DataContext as ResultsViewModel;
+            var vm = (ResultsViewModel) DataContext;
             var newResults = newRawResults.Select(r => new ResultViewModel(r)).ToList();
             vm.Results.Update(newResults);
-            vm.SelectedResult = vm.Results[0];
+            vm.SelectedIndex = 0;
         }
         
 
@@ -25,7 +26,7 @@ namespace Wox
             InitializeComponent();
         }
 
-        private void lbResults_SelectionChanged(object sender, SelectionChangedEventArgs e)
+        private void OnSelectionChanged(object sender, SelectionChangedEventArgs e)
         {
             if (e.AddedItems.Count > 0 && e.AddedItems[0] != null)
             {
@@ -33,5 +34,9 @@ namespace Wox
             }
         }
 
+        private void OnMouseEnter(object sender, MouseEventArgs e)
+        {
+            ((ListBoxItem) sender).IsSelected = true;
+        }
     }
 }

Wox/ViewModel/MainViewModel.cs

@@ -167,30 +167,33 @@ namespace Wox.ViewModel
                 Process.Start("http://doc.getwox.com");
             });
 
-            OpenResultCommand = new RelayCommand(o =>
+            OpenResultCommand = new RelayCommand(index =>
             {
                 var results = ContextMenuVisibility.IsVisible() ? ContextMenu : Results;
 
-                if (o != null)
+                if (index != null)
                 {
-                    var index = int.Parse(o.ToString());
+                    results.SelectedIndex = int.Parse(index.ToString());
-                    results.SelectResult(index);
                 }
 
-                var result = results.SelectedResult.RawResult;
+                var result = results.SelectedItem?.RawResult;
-                bool hideWindow = result.Action(new ActionContext
+                if (result != null) // SelectedItem returns null if selection is empty.
                 {
-                    SpecialKeyState = GlobalHotkey.Instance.CheckModifiers()
+                    bool hideWindow = result.Action(new ActionContext
-                });
+                    {
-                if (hideWindow)
+                        SpecialKeyState = GlobalHotkey.Instance.CheckModifiers()
-                {
+                    });
-                    MainWindowVisibility = Visibility.Collapsed;
-                }
 
-                if (!ContextMenuVisibility.IsVisible())
+                    if (hideWindow)
-                {
+                    {
-                    _userSelectedRecord.Add(result);
+                        MainWindowVisibility = Visibility.Collapsed;
-                    _queryHistory.Add(result.OriginQuery.RawQuery);
+                    }
+
+                    if (!ContextMenuVisibility.IsVisible())
+                    {
+                        _userSelectedRecord.Add(result);
+                        _queryHistory.Add(result.OriginQuery.RawQuery);
+                    }
                 }
             });
 
@@ -198,19 +201,23 @@ namespace Wox.ViewModel
             {
                 if (!ContextMenuVisibility.IsVisible())
                 {
-                    var result = Results.SelectedResult.RawResult;
+                    var result = Results.SelectedItem?.RawResult;
-                    var id = result.PluginID;
 
-                    var menus = PluginManager.GetContextMenusForPlugin(result);
+                    if (result != null) // SelectedItem returns null if selection is empty.
-                    menus.Add(ContextMenuTopMost(result));
-                    menus.Add(ContextMenuPluginInfo(id));
-
-                    ContextMenu.Clear();
-                    Task.Run(() =>
                     {
-                        ContextMenu.AddResults(menus, id);
+                        var id = result.PluginID;
-                    }, _updateToken);
+
-                    ContextMenuVisibility = Visibility.Visible;
+                        var menus = PluginManager.GetContextMenusForPlugin(result);
+                        menus.Add(ContextMenuTopMost(result));
+                        menus.Add(ContextMenuPluginInfo(id));
+
+                        ContextMenu.Clear();
+                        Task.Run(() =>
+                        {
+                            ContextMenu.AddResults(menus, id);
+                        }, _updateToken);
+                        ContextMenuVisibility = Visibility.Visible;
+                    }
                 }
                 else
                 {

Wox/ViewModel/ResultsViewModel.cs

@@ -4,12 +4,10 @@ using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.ComponentModel;
 using System.Linq;
-using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Data;
 using Wox.Core.UserSettings;
 using Wox.Plugin;
-using Wox.Storage;
 
 namespace Wox.ViewModel
 {
@@ -17,7 +15,7 @@ namespace Wox.ViewModel
     {
         #region Private Fields
 
-        private ResultViewModel _selectedResult;
+        private int _selectedIndex;
         public ResultCollection Results { get; }
         private Thickness _margin;
 
@@ -38,35 +36,17 @@ namespace Wox.ViewModel
 
         public int MaxHeight => _settings.MaxResultsToShow * 50;
 
-        public ResultViewModel SelectedResult
+        public int SelectedIndex
         {
-            get
+            get { return _selectedIndex; }
-            {
-                return _selectedResult;
-            }
             set
             {
-                if (value != null)
+                _selectedIndex = value;
-                {
-                    if (_selectedResult != null)
-                    {
-                        _selectedResult.IsSelected = false;
-                    }
-
-                    _selectedResult = value;
-
-                    if (_selectedResult != null)
-                    {
-                        _selectedResult.IsSelected = true;
-                    }
-
-                }
-
                 OnPropertyChanged();
-
             }
         }
 
+        public ResultViewModel SelectedItem { get; set; }
         public Thickness Margin
         {
             get
@@ -98,76 +78,44 @@ namespace Wox.ViewModel
             return index;
         }
 
+        private int NewIndex(int i)
+        {
+            var n = Results.Count;
+            if (n > 0)
+            {
+                i = (n + i) % n;
+                return i;
+            }
+            else
+            {
+                // SelectedIndex returns -1 if selection is empty.
+                return -1;
+            }
+        }
+
+
         #endregion
 
         #region Public Methods
 
-        public void SelectResult(int index)
-        {
-            if (index <= Results.Count - 1)
-            {
-                SelectedResult = Results[index];
-            }
-        }
-
-        public void SelectResult(ResultViewModel result)
-        {
-            int i = Results.IndexOf(result);
-            SelectResult(i);
-        }
-
         public void SelectNextResult()
         {
-            if (Results.Count > 0 && SelectedResult != null)
+            SelectedIndex = NewIndex(SelectedIndex + 1);
-            {
-                var index = Results.IndexOf(SelectedResult);
-                if (index == Results.Count - 1)
-                {
-                    index = -1;
-                }
-                SelectedResult = Results.ElementAt(index + 1);
-            }
         }
 
         public void SelectPrevResult()
         {
-            if (Results.Count > 0 && SelectedResult != null)
+            SelectedIndex = NewIndex(SelectedIndex - 1);
-            {
-                var index = Results.IndexOf(SelectedResult);
-                if (index == 0)
-                {
-                    index = Results.Count;
-                }
-                SelectedResult = Results.ElementAt(index - 1);
-            }
         }
 
         public void SelectNextPage()
         {
-            if (Results.Count > 0 && SelectedResult != null)
+            SelectedIndex = NewIndex(SelectedIndex + _settings.MaxResultsToShow);
-            {
-                var index = Results.IndexOf(SelectedResult);
-                index += 5;
-                if (index > Results.Count - 1)
-                {
-                    index = Results.Count - 1;
-                }
-                SelectedResult = Results.ElementAt(index);
-            }
         }
 
         public void SelectPrevPage()
         {
-            if (Results.Count > 0 && SelectedResult != null)
+            SelectedIndex = NewIndex(SelectedIndex - _settings.MaxResultsToShow);
-            {
-                var index = Results.IndexOf(SelectedResult);
-                index -= 5;
-                if (index < 0)
-                {
-                    index = 0;
-                }
-                SelectedResult = Results.ElementAt(index);
-            }
         }
 
         public void Clear()
@@ -239,7 +187,7 @@ namespace Wox.ViewModel
                 if (Results.Count > 0)
                 {
                     Margin = new Thickness { Top = 8 };
-                    SelectedResult = Results[0];
+                    SelectedIndex = 0;
                 }
                 else
                 {
@@ -314,6 +262,8 @@ namespace Wox.ViewModel
             }
         }
 
+
+        public ResultViewModel this[int selectedIndex] => Results[selectedIndex];
     }
 
 }