Umbraco uses Notifications (similar to the Observer pattern) to allow you to hook into the workflow process for the backoffice. For example, notifications allow you to execute some code every time a page is published.
Notifications
All notifications reside in the Umbraco.Cms.Core.Notifications namespace and are postfixed with Notification.
Available notifications typically exist in pairs, with "before" and "after" notifications. For example, the ContentService class has the concept of publishing and published notifications. So, there is both a ContentPublishingNotification and a ContentPublishedNotification notification.
The notification to use depends on what you want to achieve. If you want to be able to cancel the action, you would use the CancelOperation method on the "before" notification. See the sample in ContentService Notifications. If you want to execute some code after the publishing has succeeded, then you would use the "after" notification.
Registering Notifications
Check the Notification Handler article to learn more about notification handlers lifetime, async notification handler and how to register the notification handlers.
List of Notifications
Below you can find a list of most used object notifications.
You can find a list of all supported notifications in the API Docs.
Content, Media, and Member notifications
ContentService Notifications
The ContentService class is the most commonly used type when extending Umbraco using notifications. ContentService implements IContentService. It provides access to operations involving IContent.
Below you can find a list of the most common ContentService object notifications.
Useful for manipulating the model before it is sent to an editor in the backoffice. It could be used to set a default value of a property on a new document.
Creating and publishing your own custom notifications
Umbraco uses notifications to allow people to hook into different workflow processes. This notification pattern is extensible, allowing you to create and publish custom notifications, and other people to observe and hook into your custom processes. This approach can be useful when creating Umbraco packages. For more information on how you create and publish your own notifications, see the creating and publishing notifications article.
Showing messages in the CMS
When handling notifications for CMS actions, you can inform the Umbraco user of the status of your notification. This is done by adding to the notification.Messages property within the Handle function.
This could be used to inform the user to an additional operation that has been performed, or alert them to an error that has occoured.
For example, in a ContentTypeSavedNotification:
public void Handle(TemplateSavedNotification notification)
{
bool success = DoAdditionalCode();
if (success)
{
//on success
notification.Messages.Add(new EventMessage("Save Successful",
"The content was saved successfully",
EventMessageType.Success));
}
else
{
//on error
notification.Messages.Add(new EventMessage("An Error occoured",
"Detail about the error",
EventMessageType.Error));
}
}
Samples
Below you can find some articles with some examples using Notifications.
