feat: add demo.

demo/Ursa.Demo/Pages/PopConfirmDemo.axaml

@@ -0,0 +1,19 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:u="https://irihi.tech/ursa"
+             xmlns:viewModels="clr-namespace:Ursa.Demo.ViewModels"
+             mc:Ignorable="d" d:DesignWidth="800"
+             d:DesignHeight="450"
+             x:DataType="viewModels:PopConfirmDemoViewModel"
+             x:Class="Ursa.Demo.Pages.PopConfirmDemo">
+    <StackPanel HorizontalAlignment="Left">
+        <u:PopConfirm PopupHeader="Header" PopupContent="Content" 
+                     ConfirmCommand="{Binding Path=ConfirmCommand}"
+                     CancelCommand="{Binding Path=CancelCommand}"
+                     >
+            <Button Content="Hello World"></Button>
+        </u:PopConfirm>
+    </StackPanel>
+</UserControl>

demo/Ursa.Demo/Pages/PopConfirmDemo.axaml.cs

@@ -0,0 +1,25 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using Ursa.Controls;
+using Ursa.Demo.ViewModels;
+
+namespace Ursa.Demo.Pages;
+
+public partial class PopConfirmDemo : UserControl
+{
+    public PopConfirmDemo()
+    {
+        InitializeComponent();
+    }
+
+    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        base.OnAttachedToVisualTree(e);
+        if (this.DataContext is not PopConfirmDemoViewModel vm) return;
+        var manager = WindowToastManager.TryGetToastManager(TopLevel.GetTopLevel(this), out var m)
+            ? m
+            : new WindowToastManager(TopLevel.GetTopLevel(this));
+        vm.ToastManager = manager;
+    }
+}

demo/Ursa.Demo/ViewModels/MainViewViewModel.cs

@@ -69,6 +69,7 @@ public partial class MainViewViewModel : ViewModelBase
             MenuKeys.MenuKeyNumPad => new NumPadDemoViewModel(),
             MenuKeys.MenuKeyPagination => new PaginationDemoViewModel(),
             MenuKeys.MenuKeyPinCode => new PinCodeDemoViewModel(),
+            MenuKeys.MenuKeyPopConfirm => new PopConfirmDemoViewModel(),
             MenuKeys.MenuKeyRangeSlider => new RangeSliderDemoViewModel(),
             MenuKeys.MenuKeyRating => new RatingDemoViewModel(),
             MenuKeys.MenuKeyScrollToButton => new ScrollToButtonDemoViewModel(),

demo/Ursa.Demo/ViewModels/MenuViewModel.cs

@@ -44,6 +44,7 @@ public class MenuViewModel : ViewModelBase
                     new() { MenuHeader = "Loading", Key = MenuKeys.MenuKeyLoading, Status = "Updated" },
                     new() { MenuHeader = "Message Box", Key = MenuKeys.MenuKeyMessageBox },
                     new() { MenuHeader = "Notification", Key = MenuKeys.MenuKeyNotification },
+                    new() { MenuHeader = "PopConfirm", Key = MenuKeys.MenuKeyPopConfirm },
                     new() { MenuHeader = "Toast", Key = MenuKeys.MenuKeyToast },
                     new() { MenuHeader = "Skeleton", Key = MenuKeys.MenuKeySkeleton },
                 }
@@ -135,6 +136,7 @@ public static class MenuKeys
     public const string MenuKeyNumPad = "NumPad";
     public const string MenuKeyPagination = "Pagination";
     public const string MenuKeyPinCode = "PinCode";
+    public const string MenuKeyPopConfirm = "PopConfirm";
     public const string MenuKeyRangeSlider = "RangeSlider";
     public const string MenuKeyRating = "Rating";
     public const string MenuKeyScrollToButton = "ScrollToButton";

demo/Ursa.Demo/ViewModels/PopConfirmDemoViewModel.cs

@@ -0,0 +1,31 @@
+using System.Windows.Input;
+using Avalonia.Controls.Notifications;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using Ursa.Controls;
+
+namespace Ursa.Demo.ViewModels;
+
+public partial class PopConfirmDemoViewModel: ObservableObject
+{
+    internal WindowToastManager? ToastManager { get; set; }
+    
+    public ICommand ConfirmCommand { get; }
+    public ICommand CancelCommand { get; }
+    
+    public PopConfirmDemoViewModel()
+    {
+        ConfirmCommand = new RelayCommand(OnConfirm);
+        CancelCommand = new RelayCommand(OnCancel);
+    }
+    
+    private void OnConfirm()
+    {
+        ToastManager?.Show(new Toast("Confirmed"), type: NotificationType.Success, classes: ["Light"]);
+    }
+    
+    private void OnCancel()
+    {
+        ToastManager?.Show(new Toast("Canceled"), type:NotificationType.Error, classes: ["Light"]);
+    }
+}