feat: add async command support.

demo/Ursa.Demo/ViewModels/PopConfirmDemoViewModel.cs

@@ -1,3 +1,4 @@
+using System.Threading.Tasks;
 using System.Windows.Input;
 using Avalonia.Controls.Notifications;
 using CommunityToolkit.Mvvm.ComponentModel;
@@ -15,12 +16,13 @@ public partial class PopConfirmDemoViewModel: ObservableObject
     
     public PopConfirmDemoViewModel()
     {
-        ConfirmCommand = new RelayCommand(OnConfirm);
+        ConfirmCommand = new AsyncRelayCommand(OnConfirm);
         CancelCommand = new RelayCommand(OnCancel);
     }
     
-    private void OnConfirm()
+    private async Task OnConfirm()
     {
+        await Task.Delay(3000);
         ToastManager?.Show(new Toast("Confirmed"), type: NotificationType.Success, classes: ["Light"]);
     }
     

src/Ursa.Themes.Semi/Controls/PopConfirm.axaml

@@ -7,14 +7,24 @@
             <ControlTemplate TargetType="u:PopConfirm">
                 <Panel>
                     <ContentPresenter Content="{TemplateBinding Content}" ContentTemplate="{TemplateBinding ContentTemplate}"/>
-                    <Popup IsOpen="True">
+                    <Popup IsOpen="True" 
+                           Name="{x:Static u:PopConfirm.PART_Popup}"
+                           Placement="Bottom" >
                         <Border Theme="{DynamicResource CardBorder}">
                             <StackPanel>
                                 <ContentPresenter Content="{TemplateBinding PopupHeader}" ContentTemplate="{TemplateBinding PopupHeaderTemplate}"/>
                                 <ContentPresenter Content="{TemplateBinding PopupContent}" ContentTemplate="{TemplateBinding PopupContentTemplate}"/>
                                 <StackPanel Orientation="Horizontal">
-                                    <Button Content="Confirm" Command="{TemplateBinding ConfirmCommand}" CommandParameter="{TemplateBinding ConfirmCommandParameter}"/>
+                                    <Button 
-                                    <Button Content="Cancel" Command="{TemplateBinding CancelCommand}" CommandParameter="{TemplateBinding CancelCommandParameter}"/>
+                                        Name="{x:Static u:PopConfirm.PART_ConfirmButton}"
+                                        Content="Confirm" 
+                                        Command="{TemplateBinding ConfirmCommand}" 
+                                        CommandParameter="{TemplateBinding ConfirmCommandParameter}"/>
+                                    <Button 
+                                        Name="{x:Static u:PopConfirm.PART_CancelButton}"
+                                        Content="Cancel" 
+                                        Command="{TemplateBinding CancelCommand}" 
+                                        CommandParameter="{TemplateBinding CancelCommandParameter}"/>
                                 </StackPanel>
                             </StackPanel>
                         </Border>

src/Ursa/Controls/PopConfirm/PopConfirm.cs

@@ -1,9 +1,11 @@
+using System.ComponentModel;
 using System.Windows.Input;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
+using Avalonia.Interactivity;
 using Avalonia.LogicalTree;
 using Irihi.Avalonia.Shared.Helpers;
 
@@ -11,6 +13,14 @@ namespace Ursa.Controls;
 
 public class PopConfirm: ContentControl
 {
+    public const string PART_ConfirmButton = "PART_ConfirmButton";
+    public const string PART_CancelButton = "PART_CancelButton";
+    public const string PART_Popup = "PART_Popup";
+    
+    private Button? _confirmButton;
+    private Button? _cancelButton;
+    private Popup? _popup;
+    
     public static readonly StyledProperty<object?> PopupHeaderProperty = AvaloniaProperty.Register<PopConfirm, object?>(
         nameof(PopupHeader));
 
@@ -100,14 +110,7 @@ public class PopConfirm: ContentControl
 
     private void OnCommandChanged(AvaloniaPropertyChangedEventArgs<ICommand?> args)
     {
-        var newValue = args.GetNewValue<ICommand>();
+        
-        newValue.CanExecuteChanged += (sender, e) =>
-        {
-            if (args.Sender is PopConfirm popconfirm)
-            {
-                var b = newValue.CanExecute(this.ConfirmCommandParameter);
-            }
-        };
     }
 
     public PopConfirm()
@@ -129,8 +132,37 @@ public class PopConfirm: ContentControl
     protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
     {
         base.OnApplyTemplate(e);
+        _confirmButton = e.NameScope.Find<Button>(PART_ConfirmButton);
+        _cancelButton = e.NameScope.Find<Button>(PART_CancelButton);
+        _popup = e.NameScope.Find<Popup>(PART_Popup);
+        Button.ClickEvent.AddHandler(OnButtonClicked, _confirmButton, _cancelButton);
     }
 
+    private void OnButtonClicked(object sender, RoutedEventArgs e)
+    {
+        // This is a hack for MVVM toolkit that uses INotifyPropertyChanged for async command. It counts the number of
+        // IsRunning property changes to determine when the command is finished.
+        if (sender is Button button &&  button.Command is INotifyPropertyChanged inpc)
+        {
+            var count = 0;
+            void OnCommandPropertyChanged(object? sender, PropertyChangedEventArgs args)
+            {
+                if (args.PropertyName != "IsRunning") return;
+                count++;
+                if (count != 2) return;
+                inpc.PropertyChanged -= OnCommandPropertyChanged;
+                _popup?.SetValue(Popup.IsOpenProperty, false);
+            }
+            inpc.PropertyChanged += OnCommandPropertyChanged;
+        }
+        else
+        {
+            _popup?.SetValue(Popup.IsOpenProperty, false);
+        }
+    }
+
+    
+
     private IDisposable? _childChangeDisposable;
 
     protected override bool RegisterContentPresenter(ContentPresenter presenter)