WindowNotificationManager

The WindowNotificationManager provides a built-in notification popup system. It displays toast-style messages at a configurable position within a window. You can use it to inform users about completed operations, warnings, errors, or other events without blocking interaction with the rest of the UI.

Useful properties

Property	Type	Description
Position	NotificationPosition	Where notifications appear. Options: TopLeft, TopCenter, TopRight, BottomLeft, BottomCenter, BottomRight. Default: TopRight.
MaxItems	int	Maximum number of notifications visible at one time. Default: 5.

Notification properties

The built-in Notification class exposes these properties:

Property	Type	Description
Title	string	The notification title text.
Message	string	The notification body text.
Type	NotificationType	The severity level: Information, Success, Warning, or Error.
Expiration	TimeSpan	Time before the notification auto-dismisses. Set to TimeSpan.Zero to require manual dismissal.

Setting up

Register a WindowNotificationManager in your window, typically in code-behind or through a view model reference:

public partial class MainWindow : Window
{
    private WindowNotificationManager _notificationManager;

    public MainWindow()
    {
        InitializeComponent();

        _notificationManager = new WindowNotificationManager(this)
        {
            Position = NotificationPosition.BottomRight,
            MaxItems = 3
        };
    }
}

You can also declare the WindowNotificationManager in XAML if you prefer a markup-based approach:

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Class="MyApp.MainWindow">
    <Panel>
        <WindowNotificationManager x:Name="NotificationManager"
                                   Position="TopRight"
                                   MaxItems="5" />
        <!-- Your other content here -->
    </Panel>
</Window>

You then access the manager from code-behind:

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        var manager = this.FindControl<WindowNotificationManager>("NotificationManager");
    }
}

Showing a notification

Call Show with a Notification object:

_notificationManager.Show(new Notification(
    "File saved",
    "Your document has been saved successfully.",
    NotificationType.Success,
    TimeSpan.FromSeconds(3)));

If you omit the Expiration parameter, the notification uses the default expiration time. To keep a notification visible until the user dismisses it manually, pass TimeSpan.Zero:

_notificationManager.Show(new Notification(
    "Action required",
    "Please review the pending changes before continuing.",
    NotificationType.Warning,
    TimeSpan.Zero));

Notification types

Use the NotificationType enum to convey severity. The built-in theme applies distinct colors to each type:

// Informational (default blue)
_notificationManager.Show(new Notification("Info", "Operation started.", NotificationType.Information));

// Success (green)
_notificationManager.Show(new Notification("Done", "Upload complete.", NotificationType.Success));

// Warning (yellow/orange)
_notificationManager.Show(new Notification("Warning", "Disk space is low.", NotificationType.Warning));

// Error (red)
_notificationManager.Show(new Notification("Error", "Connection failed.", NotificationType.Error));

Closing notifications programmatically

You can close a specific notification or clear all notifications from code:

var notification = new Notification("Processing", "Working...", NotificationType.Information, TimeSpan.Zero);
_notificationManager.Show(notification);

// Close a specific notification
_notificationManager.Close(notification);

// Clear all active notifications
_notificationManager.ClearAll();

This is useful when a long-running operation completes and you want to replace a progress notification with a result notification:

var progressNotification = new Notification(
    "Uploading",
    "Sending files to the server...",
    NotificationType.Information,
    TimeSpan.Zero);

_notificationManager.Show(progressNotification);

// Later, when the upload finishes:
_notificationManager.Close(progressNotification);
_notificationManager.Show(new Notification(
    "Upload complete",
    "All files have been sent successfully.",
    NotificationType.Success,
    TimeSpan.FromSeconds(3)));

Custom notification content

Implement INotification to provide custom notification data:

public class CustomNotification : INotification
{
    public string Title { get; set; }
    public string Message { get; set; }
    public NotificationType Type { get; set; }
    public TimeSpan Expiration { get; set; }
    public string ActionText { get; set; }
    public Action OnAction { get; set; }

    public void OnClose()
    {
        // Clean up when dismissed
    }

    public void OnClick()
    {
        OnAction?.Invoke();
    }
}

You can then show your custom notification the same way:

_notificationManager.Show(new CustomNotification
{
    Title = "New message",
    Message = "You have a new message from support.",
    Type = NotificationType.Information,
    Expiration = TimeSpan.FromSeconds(5),
    ActionText = "View",
    OnAction = () => NavigateToMessages()
});

Positioning

Control where notifications appear by setting Position:

// Top-right corner (default)
_notificationManager.Position = NotificationPosition.TopRight;

// Bottom-center (useful for mobile-style toasts)
_notificationManager.Position = NotificationPosition.BottomCenter;

The six available positions are:

Position	Description
TopLeft	Top-left corner of the window.
TopCenter	Top edge, centered horizontally.
TopRight	Top-right corner of the window (default).
BottomLeft	Bottom-left corner of the window.
BottomCenter	Bottom edge, centered horizontally.
BottomRight	Bottom-right corner of the window.

MVVM pattern

Expose a notification manager through a service so your view models can show notifications without referencing UI types directly:

public interface INotificationService
{
    void ShowInfo(string title, string message);
    void ShowSuccess(string title, string message);
    void ShowWarning(string title, string message);
    void ShowError(string title, string message);
}

public class NotificationService : INotificationService
{
    private readonly WindowNotificationManager _manager;

    public NotificationService(WindowNotificationManager manager)
    {
        _manager = manager;
    }

    public void ShowInfo(string title, string message) =>
        _manager.Show(new Notification(title, message, NotificationType.Information));

    public void ShowSuccess(string title, string message) =>
        _manager.Show(new Notification(title, message, NotificationType.Success));

    public void ShowWarning(string title, string message) =>
        _manager.Show(new Notification(title, message, NotificationType.Warning));

    public void ShowError(string title, string message) =>
        _manager.Show(new Notification(title, message, NotificationType.Error));
}

Register the service in your application startup and inject it into view models that need to display notifications:

public class MyViewModel
{
    private readonly INotificationService _notifications;

    public MyViewModel(INotificationService notifications)
    {
        _notifications = notifications;
    }

    public void SaveDocument()
    {
        // Perform save logic...
        _notifications.ShowSuccess("Saved", "Your document has been saved.");
    }
}

See also

• How to show notifications and toasts
• Popup
• ToolTip