Lazy load custom preview

Author: VictoriousRaptor

Flow.Launcher/MainWindow.xaml

@@ -481,7 +481,7 @@
                             DataContext="{Binding SelectedItem, ElementName=ResultListBox}"
                             Style="{DynamicResource PreviewBorderStyle}" 
                             Visibility="{Binding ShowCustomizedPreview}">
-                            <ContentControl Content="{Binding Result.PreviewPanel.Value}" />
+                            <ContentControl Content="{Binding CustomPreviewPanel}" />
                         </Border>
                     </Grid>
                 </Grid>

Flow.Launcher/ViewModel/MainViewModel.cs

@@ -462,7 +462,7 @@ private void ShowPreview()
         {
             ResultAreaColumn = 1;
             PreviewVisible = true;
-            Results.SelectedItem?.LoadPreviewImage();
+            Results.SelectedItem?.LoadPreviewPanel();
         }
 
         private void HidePreview()
@@ -487,7 +487,7 @@ private void UpdatePreview()
         {
             if (PreviewVisible)
             {
-                Results.SelectedItem?.LoadPreviewImage();
+                Results.SelectedItem?.LoadPreviewPanel();
             }
         }
 

Flow.Launcher/ViewModel/ResultViewModel.cs

@@ -9,6 +9,7 @@
 using System.IO;
 using System.Drawing.Text;
 using System.Collections.Generic;
+using System.Windows.Controls;
 
 namespace Flow.Launcher.ViewModel
 {
@@ -130,8 +131,10 @@ public Visibility ShowGlyph
             ? Result.SubTitle
             : Result.SubTitleToolTip;
 
+        public UserControl CustomPreviewPanel { get; set; } = null;
+
         private volatile bool ImageLoaded;
-        private volatile bool PreviewImageLoaded;
+        private volatile bool PreviewPanelLoaded;
 
         private ImageSource image = ImageLoader.LoadingImage;
         private ImageSource previewImage = ImageLoader.LoadingImage;
@@ -214,12 +217,23 @@ private async Task LoadPreviewImageAsync()
             }
         }
 
-        public void LoadPreviewImage()
+        public void LoadPreviewPanel()
         {
-            if (!PreviewImageLoaded && ShowIcon == Visibility.Visible)
+            if (ShowDefaultPreview == Visibility.Visible)
             {
-                PreviewImageLoaded = true;
-                _ = LoadPreviewImageAsync();
+                if (!PreviewPanelLoaded && ShowIcon == Visibility.Visible)
+                {
+                    PreviewPanelLoaded = true;
+                    _ = LoadPreviewImageAsync();
+                }
+            }
+            else if (ShowCustomizedPreview == Visibility.Visible)
+            {
+                if (!PreviewPanelLoaded)
+                {
+                    PreviewPanelLoaded = true;
+                    CustomPreviewPanel = Result.PreviewPanel.Value;
+                }
             }
         }