Handling object events

Objects include all data structures used within Kentico, for example user accounts, forums, page templates, search indexes, or setting keys. By handling the events that occur during the life cycle of objects, you can add custom functionality to almost any part of the system. In the API, objects are represented by Info classes.

Use the following classes to access the object events:

  • ObjectEvents - events triggered for all object types
  • <name>Info.TYPEINFO.Events - events triggered only for a specific object type, for example: UserInfo.TYPEINFO.Events

See the Global event reference for information about the available events.

Note: Within the context of event handling, objects do NOT include pages in the website content tree. Use the DocumentEvents class to assign handlers to events that the system triggers for pages.

Example

The following example demonstrates how to use event handlers to customize the behavior of a specific type of object.

The sample code extends the functionality of forum groups by creating a handler for the Insert.After event of the ForumGroupInfo object type. This event occurs whenever a forum group is created. The custom logic automatically adds an initial child forum for every new forum group.

  1. Open your Kentico project in Visual Studio (using the WebSite.sln or WebApp.sln file).
  2. Create a custom module class.
    • Either add the class into a custom project within the Kentico solution (recommended) or directly into the Kentico web project (into a custom folder under the CMSApp project for web application installations, into the App_Code folder for web site installations).
  3. Override the module's OnInit method and assign a handler method to the ForumGroupInfo.TYPEINFO.Events.Insert.After event.
using CMS;
using CMS.DataEngine;
using CMS.Forums;
using CMS.Helpers;

// Registers the custom module into the system
[assembly: RegisterModule(typeof(CustomForumModule))]

public class CustomForumModule : Module
{
	// Module class constructor, the system registers the module under the name "CustomForums"
	public CustomForumModule()
		: base("CustomForums")
	{
	}

	// Contains initialization code that is executed when the application starts
	protected override void OnInit()
	{
		base.OnInit();

		// Assigns a handler to the Insert.After event for the ForumGroupInfo object type
		// This event occurs after the creation of every new forum group
		ForumGroupInfo.TYPEINFO.Events.Insert.After += ForumGroup_InsertAfterEventHandler;
	}

	/// <summary>
	/// Automatically creates a child forum for new forum groups
	/// </summary>
	private void ForumGroup_InsertAfterEventHandler(object sender, ObjectEventArgs e)
	{
		// Checks that the forum group was successfully created
		if (e.Object != null)
		{
			// Gets an info object representing the new forum group
			ForumGroupInfo forumGroup = (ForumGroupInfo)e.Object;

			// Creates the child forum object
			ForumInfo newForum = new ForumInfo()
			{
				// Sets the child forum's properties
				ForumDisplayName = forumGroup.GroupDisplayName + " - General",
				ForumName = forumGroup.GroupName + "_General",
				ForumGroupID = forumGroup.GroupID,
				ForumSiteID = forumGroup.GroupSiteID,

				ForumOpen = true,
				ForumModerated = false,
				AllowAccess = SecurityAccessEnum.AllUsers,
				ForumThreads = 0,
				ForumPosts = 0
			};

			// Saves the child forum to the database
			ForumInfoProvider.SetForumInfo(newForum);
		}
	}
}

To try out the functionality of the custom event handler, create a new forum group on any website:

  1. Open the Forums application.
  2. Click New forum group.
  3. Type a name into the Group display name field of the new forum group.
  4. Click Save.

The system automatically creates a child forum named after the forum group (with a " - General" suffix).


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