Скачать или смотреть How to Effectively Notify All Windows When a Static Property Changes in WPF C# Applications

Learn how to update all ListViews across multiple windows in a WPF application when a static property changes, improving your application's responsiveness and user experience.
---
This video is based on the question https://stackoverflow.com/q/69839762/ asked by the user 'nsv' ( https://stackoverflow.com/u/17312935/ ) and on the answer https://stackoverflow.com/a/69840094/ provided by the user 'nsv' ( https://stackoverflow.com/u/17312935/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to notify all windows that static property has changed?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Effectively Notify All Windows When a Static Property Changes in WPF C- Applications

When developing a WPF (Windows Presentation Foundation) application using the MVVM (Model-View-ViewModel) pattern, you might encounter a common issue: how to refresh all ListViews across different windows when a static property is updated. This is particularly relevant when managing collections, such as tasks in a task manager application. This guide provides a clear solution to ensure that all windows reflect the most current data without the need for cumbersome workarounds.

The Problem

Imagine having multiple windows in your WPF application displaying tasks from a static property defined in App.xaml.cs. When you add a new task, you want every ListView across these windows to update immediately. However, you quickly realize that simply redefining the static property doesn't trigger the necessary UI updates.

Here's a glimpse at the static property in App.xaml.cs:

[[See Video to Reveal this Text or Code Snippet]]

The issue lies in the fact that when you redefine the AllTasks property, you are creating a new instance of ObservableCollection, effectively breaking the bindings that are already established with the ListViews.

Solution Overview

To resolve the problem, the solution is straightforward. Instead of creating a new ObservableCollection each time you add a task, you should modify the existing collection directly. This allows all bound ListViews to automatically receive updates and reflect the new state of the collection.

Steps to Implement the Solution

Update the Task Addition Method: Instead of resetting the AllTasks property when a new task is added, use the Add method to add the new task directly to the existing ObservableCollection.

Here’s how to update the method:

Change this:

[[See Video to Reveal this Text or Code Snippet]]

To this:

[[See Video to Reveal this Text or Code Snippet]]

By doing this, the existing ObservableCollection remains intact and all UI instances reflecting this collection will see the update.

Example of the Updated Code

Let's integrate this change into your current task addition logic:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By applying this simple yet effective strategy, you can ensure that all ListView controls across different windows stay in sync with your application's data. This approach not only solves the immediate problem but also enhances the user experience by providing a responsive UI.

In your journey through WPF and MVVM development, remember that you don't always need to redefine properties to see changes reflected in your UI. Instead, make direct modifications to your collections, especially when working with ObservableCollection.

Thanks to -Nawed Nabi Zada for the insight that led to this improvement!