fix warning for null thumbnail after deleting project from list

Author: unitycoder

UnityLauncherPro/Converters/ThumbnailConverter.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Globalization;
 using System.IO;
+using System.Windows;
 using System.Windows.Data;
 using System.Windows.Media.Imaging;
 
@@ -10,6 +11,12 @@ public class ThumbnailConverter : IValueConverter
     {
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
+            // Return UnsetValue if no project is selected
+            if (value == null)
+            {
+                return DependencyProperty.UnsetValue;
+            }
+
             if (value is Project project)
             {
                 if (!string.IsNullOrEmpty(project.Path))
@@ -20,6 +27,13 @@ public object Convert(object value, Type targetType, object parameter, CultureIn
                     {
                         try
                         {
+                            // Check if this is for Width/Height parameter
+                            if (parameter != null && (parameter.ToString() == "Width" || parameter.ToString() == "Height"))
+                            {
+                                return 64.0; // Return default dimension
+                            }
+
+                            // For Source binding, load the bitmap
                             var bitmap = new BitmapImage();
                             bitmap.BeginInit();
                             bitmap.CacheOption = BitmapCacheOption.OnLoad;
@@ -40,14 +54,25 @@ public object Convert(object value, Type targetType, object parameter, CultureIn
                         }
                         catch
                         {
-                            // Ignore and fall back to null
+                            // Ignore and fall back to UnsetValue for Source, or 64.0 for dimensions
+                            if (parameter != null && (parameter.ToString() == "Width" || parameter.ToString() == "Height"))
+                            {
+                                return 64.0;
+                            }
+                            return DependencyProperty.UnsetValue;
                         }
                     }
                 }
-                return null;
+
+                // Project path doesn't exist or no thumbnail found
+                if (parameter != null && (parameter.ToString() == "Width" || parameter.ToString() == "Height"))
+                {
+                    return 64.0; // Return default dimension
+                }
+                return DependencyProperty.UnsetValue;
             }
 
-            return null;
+            return DependencyProperty.UnsetValue;
         }
 
         public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)