refactor<*>: rewrite all with AvaloniaUI

src/Views/Apply.axaml.cs

@@ -0,0 +1,24 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.Platform.Storage;
+
+namespace SourceGit.Views {
+    public partial class Apply : UserControl {
+        public Apply() {
+            InitializeComponent();
+        }
+
+        private async void SelectPatchFile(object sender, RoutedEventArgs e) {
+            var topLevel = TopLevel.GetTopLevel(this);
+            if (topLevel == null) return;
+
+            var options = new FilePickerOpenOptions() { AllowMultiple = false, FileTypeFilter = [ new FilePickerFileType("Patch File") { Patterns = ["*.patch"] }] };
+            var selected = await topLevel.StorageProvider.OpenFilePickerAsync(options);
+            if (selected.Count == 1) {
+                txtPatchFile.Text = selected[0].Path.LocalPath;
+            }
+
+            e.Handled = true;
+        }
+    }
+}