feat: move to menu.

demo/Ursa.Demo/ViewModels/MenuItemViewModel.cs

@@ -0,0 +1,29 @@
+using System.Collections.ObjectModel;
+using System.Windows.Input;
+using CommunityToolkit.Mvvm.Input;
+using CommunityToolkit.Mvvm.Messaging;
+
+namespace Ursa.Demo.ViewModels;
+
+public class MenuItemViewModel: ViewModelBase
+{
+    public string MenuHeader { get; set; }
+    public string MenuIconName { get; set; }
+    public string Key { get; set; }
+    
+    public bool IsSeparator { get; set; }
+    public ObservableCollection<MenuItemViewModel> Children { get; set; } = new();
+    
+    public ICommand ActivateCommand { get; set; }
+
+    public MenuItemViewModel()
+    {
+        ActivateCommand = new RelayCommand(OnActivate);
+    }
+
+    private void OnActivate()
+    {
+        if (IsSeparator) return;
+        WeakReferenceMessenger.Default.Send<string>(Key);
+    }
+}