.NET MAUI introduces a powerful multi-window feature that enables developers to create rich, multi-window experiences across different platforms. This allows users to open multiple windows within the application, enhancing productivity and flexibility. However, one key feature missing from the framework is the ability to retrieve the currently active window. This limitation can be challenging when trying to display popups, manage UI state dynamically, or interact with the user's current window context.
This article aims to provide a simple, cross-platform way to overcome this limitation by implementing a custom solution that tracks the active window in .NET MAUI.
Implementing a Custom Window Class
To track the active window, we can extend the Window class. Create a custom Window class WindowEx.
In this implementation, the WindowEx class exposes an IsActive property that indicates whether the window is currently active. The OnActivated and OnDeactivated methods are overridden to update the IsActive property accordingly.
That's it! We have a custom WindowEx class that tracks the active window state. Now, whenever you need to create a new window, use the WindowEx class instead of the default Window class.
Let's also create some extension methods.
The IsActive extension method checks if the window is an instance of WindowEx and if it is active. The GetActiveWindow method retrieves the first active window from the application's window collection.
Platform-Specific Considerations
While there is no direct cross-platform API to obtain the active window, this can be achieved using platform-specific implementations. For example, on Android, you can access the current activity's window using:
Since MAUI aims to provide a unified experience, the approach in this article offers a simple and effective cross-platform solution without relying on platform-specific code.
Conclusion
By extending the Window class and implementing the WindowEx subclass, we can reliably track the active window in .NET MAUI. The provided extension methods make it easy to check for the currently active window and use it dynamically within your application, ensuring a seamless multi-window experience.
You can find the source code on GitHub.