Make Notification properties open and some bindable

src/Avalonia.Controls/Notifications/Notification.cs

@@ -1,4 +1,7 @@
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
 
 namespace Avalonia.Controls.Notifications
 {
@@ -9,8 +12,10 @@ namespace Avalonia.Controls.Notifications
     /// This class represents a notification that can be displayed either in a window using
     /// <see cref="WindowNotificationManager"/> or by the host operating system (to be implemented).
     /// </remarks>
-    public class Notification : INotification
+    public class Notification : INotification, INotifyPropertyChanged
     {
+        private string? _title, _message;
+        
         /// <summary>
         /// Initializes a new instance of the <see cref="Notification"/> class.
         /// </summary>
@@ -35,23 +40,59 @@ namespace Avalonia.Controls.Notifications
             OnClick = onClick;
             OnClose = onClose;
         }
+        
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Notification"/> class.
+        /// </summary>
+        public Notification() : this(null, null)
+        {
+        }
 
         /// <inheritdoc/>
-        public string? Title { get; private set; }
+        public string? Title
+        {
+            get => _title;
+            set
+            {
+                if (_title != value)
+                {
+                    _title = value;
+                    OnPropertyChanged();
+                }
+            }
+        }
 
         /// <inheritdoc/>
-        public string? Message { get; private set; }
+        public string? Message
+        {
+            get => _message;
+            set
+            {
+                if (_message != value)
+                {
+                    _message = value;
+                    OnPropertyChanged();
+                }
+            }
+        }
 
         /// <inheritdoc/>
-        public NotificationType Type { get; private set; }
+        public NotificationType Type { get; set; }
 
         /// <inheritdoc/>
-        public TimeSpan Expiration { get; private set; }
+        public TimeSpan Expiration { get; set; }
 
         /// <inheritdoc/>
-        public Action? OnClick { get; private set; }
+        public Action? OnClick { get; set; }
 
         /// <inheritdoc/>
-        public Action? OnClose { get; private set; }
+        public Action? OnClose { get; set; }
+
+        public event PropertyChangedEventHandler? PropertyChanged;
+
+        protected virtual void OnPropertyChanged([CallerMemberName] string? propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
     }
 }