more export UI code

src/Utility/ObservableRangeCollection.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+
+public class ObservableRangeCollection<T> : ObservableCollection<T>
+{
+    private bool _suppressNotification = false;
+
+    protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
+    {
+        // Only raise the event if notifications are not suppressed
+        if (!_suppressNotification)
+        {
+            base.OnCollectionChanged(e);
+        }
+    }
+
+    public void AddRange(IEnumerable<T> collection)
+    {
+        if (collection == null)
+        {
+            throw new ArgumentNullException(nameof(collection));
+        }
+
+        _suppressNotification = true; // Suppress notifications during bulk add
+
+        foreach (var item in collection)
+        {
+            Items.Add(item); // Add items using the underlying IList<T>
+        }
+
+        _suppressNotification = false; // Re-enable notifications
+
+        // Raise a single Reset event to notify about the bulk change
+        OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
+    }
+}

src/Utility/Utils.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Avalonia.Controls;
+using Avalonia.Platform.Storage;
+using Avalonia.Threading;
+using MercuryConverter.UI;
+
+namespace MercuryConverter.Utility;
+
+public static class Utils
+{
+    public static string CoreCount => Environment.ProcessorCount.ToString();
+    public static async Task<string> BeginDirSelection(string title, string? startDir = null)
+    {
+        IReadOnlyList<IStorageFolder>? dirSelection = null;
+
+        await Dispatcher.UIThread.Invoke(async () =>
+        {
+            await Task.Delay(250);
+            var tl = TopLevel.GetTopLevel(MainWindow.Instance)!;
+            dirSelection = await tl.StorageProvider.OpenFolderPickerAsync
+            (
+                new FolderPickerOpenOptions
+                {
+                    Title = title,
+                    AllowMultiple = false,
+                    SuggestedStartLocation = startDir == null ? null : await tl.StorageProvider.TryGetFolderFromPathAsync(startDir),
+                }
+            );
+        });
+
+        if (dirSelection!.Count <= 0)
+        {
+            return "";
+        }
+
+        return dirSelection!.First().TryGetLocalPath()!;
+    }
+}