Use selected item for binding preview properties & Code cleanup

Author: Jack251970

Flow.Launcher/MainWindow.xaml

@@ -441,7 +441,7 @@
                         <Border
                             MinHeight="380"
                             d:DataContext="{d:DesignInstance vm:ResultViewModel}"
-                            DataContext="{Binding SelectedItem, ElementName=ResultListBox}"
+                            DataContext="{Binding SelectedItem, Mode=OneWay}"
                             Visibility="{Binding ShowDefaultPreview}">
                             <Grid
                                 Margin="0 0 10 5"
@@ -518,7 +518,7 @@
                             MaxHeight="{Binding ElementName=ResultListBox, Path=ActualHeight}"
                             Padding="0 0 10 10"
                             d:DataContext="{d:DesignInstance vm:ResultViewModel}"
-                            DataContext="{Binding SelectedItem, ElementName=ResultListBox}"
+                            DataContext="{Binding SelectedItem, Mode=OneWay}"
                             Visibility="{Binding ShowCustomizedPreview}">
                             <ContentControl Content="{Binding Result.PreviewPanel.Value}" />
                         </Border>

Flow.Launcher/ViewModel/MainViewModel.cs

@@ -162,6 +162,7 @@ public MainViewModel()
                 switch (args.PropertyName)
                 {
                     case nameof(Results.SelectedItem):
+                        SelectedItem = Results.SelectedItem;
                         UpdatePreview();
                         break;
                 }
@@ -786,6 +787,18 @@ private static string VerifyOrSetDefaultHotkey(string hotkey, string defaultHotk
 
         #region Preview
 
+        private ResultViewModel _selectedItem;
+
+        public ResultViewModel SelectedItem
+        {
+            get => _selectedItem;
+            set
+            {
+                _selectedItem = value;
+                OnPropertyChanged();
+            }
+        }
+
         public bool InternalPreviewVisible
         {
             get
@@ -884,7 +897,7 @@ private static void SwitchExternalPreview(string path, bool sendFailToast = true
         private void ShowInternalPreview()
         {
             ResultAreaColumn = ResultAreaColumnPreviewShown;
-            Results.SelectedItem?.LoadPreviewImage();
+            SelectedItem?.LoadPreviewImage();
         }
 
         private void HideInternalPreview()
@@ -939,14 +952,14 @@ when CanExternalPreviewSelectedResult(out var path):
 
                 case false
                     when InternalPreviewVisible:
-                    Results.SelectedItem?.LoadPreviewImage();
+                    SelectedItem?.LoadPreviewImage();
                     break;
             }
         }
 
         private bool CanExternalPreviewSelectedResult(out string path)
         {
-            path = Results.SelectedItem?.Result?.Preview.FilePath;
+            path = SelectedItem?.Result?.Preview.FilePath;
             return !string.IsNullOrEmpty(path);
         }
 
@@ -976,7 +989,7 @@ private void QueryContextMenu()
             var query = QueryText.ToLower().Trim();
             ContextMenu.Clear();
 
-            var selected = Results.SelectedItem?.Result;
+            var selected = SelectedItem?.Result;
 
             if (selected != null) // SelectedItem returns null if selection is empty.
             {

Flow.Launcher/ViewModel/ResultViewModel.cs

@@ -1,21 +1,21 @@
 using System;
+using System.Collections.Generic;
+using System.Drawing.Text;
+using System.IO;
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Media;
 using Flow.Launcher.Infrastructure.Image;
 using Flow.Launcher.Infrastructure.Logger;
 using Flow.Launcher.Infrastructure.UserSettings;
 using Flow.Launcher.Plugin;
-using System.IO;
-using System.Drawing.Text;
-using System.Collections.Generic;
 
 namespace Flow.Launcher.ViewModel
 {
     public class ResultViewModel : BaseModel
     {
-        private static PrivateFontCollection fontCollection = new();
-        private static Dictionary<string, string> fonts = new();
+        private static readonly PrivateFontCollection fontCollection = new();
+        private static readonly Dictionary<string, string> fonts = new();
 
         public ResultViewModel(Result result, Settings settings)
         {
@@ -39,11 +39,11 @@ public ResultViewModel(Result result, Settings settings)
                         fontFamilyPath = Path.Combine(Result.PluginDirectory, fontFamilyPath);
                     }
 
-                    if (fonts.ContainsKey(fontFamilyPath))
+                    if (fonts.TryGetValue(fontFamilyPath, out var value))
                     {
                         Glyph = glyph with
                         {
-                            FontFamily = fonts[fontFamilyPath]
+                            FontFamily = value
                         };
                     }
                     else
@@ -171,7 +171,16 @@ public ImageSource Image
 
         public ImageSource PreviewImage
         {
-            get => previewImage;
+            get
+            {
+                if (!PreviewImageLoaded)
+                {
+                    PreviewImageLoaded = true;
+                    _ = LoadPreviewImageAsync();
+                }
+
+                return previewImage;
+            }
             private set => previewImage = value;
         }
 

Flow.Launcher/ViewModel/ResultsViewModel.cs

@@ -1,6 +1,4 @@
 using System;
-using Flow.Launcher.Infrastructure.UserSettings;
-using Flow.Launcher.Plugin;
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Linq;
@@ -10,6 +8,8 @@
 using System.Windows.Data;
 using System.Windows.Documents;
 using System.Windows.Input;
+using Flow.Launcher.Infrastructure.UserSettings;
+using Flow.Launcher.Plugin;
 
 namespace Flow.Launcher.ViewModel
 {
@@ -219,7 +219,6 @@ private List<ResultViewModel> NewResults(List<Result> newRawResults, string resu
             if (newRawResults.Count == 0)
                 return Results;
 
-
             var newResults = newRawResults.Select(r => new ResultViewModel(r, _settings));
 
             return Results.Where(r => r.Result.PluginID != resultId)
@@ -241,6 +240,7 @@ private List<ResultViewModel> NewResults(ICollection<ResultsForUpdate> resultsFo
         #endregion
 
         #region FormattedText Dependency Property
+
         public static readonly DependencyProperty FormattedTextProperty = DependencyProperty.RegisterAttached(
             "FormattedText",
             typeof(Inline),
@@ -259,8 +259,7 @@ public static Inline GetFormattedText(DependencyObject textBlock)
 
         private static void FormattedTextPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
-            var textBlock = d as TextBlock;
-            if (textBlock == null) return;
+            if (d is not TextBlock textBlock) return;
 
             var inline = (Inline)e.NewValue;
 
@@ -269,6 +268,7 @@ private static void FormattedTextPropertyChanged(DependencyObject d, DependencyP
 
             textBlock.Inlines.Add(inline);
         }
+
         #endregion
 
         public class ResultCollection : List<ResultViewModel>, INotifyCollectionChanged
@@ -279,7 +279,6 @@ public class ResultCollection : List<ResultViewModel>, INotifyCollectionChanged
 
             public event NotifyCollectionChangedEventHandler CollectionChanged;
 
-
             protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
             {
                 CollectionChanged?.Invoke(this, e);
@@ -297,6 +296,7 @@ public void BulkAddAll(List<ResultViewModel> resultViews)
                 // wpf use DirectX / double buffered already, so just reset all won't cause ui flickering
                 OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
             }
+
             private void AddAll(List<ResultViewModel> Items)
             {
                 for (int i = 0; i < Items.Count; i++)
@@ -308,6 +308,7 @@ private void AddAll(List<ResultViewModel> Items)
                     OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item, i));
                 }
             }
+
             public void RemoveAll(int Capacity = 512)
             {
                 Clear();