Brian Wilson : Features

Features in Office SharePoint Server 2007

Brian Wilson — Sun, 13 Jul 2008 21:35:00 GMT

Features

Feature framework is an innovation to enhance modular provisioning. It works by grouping logical elements into scenario-driven “features”.

l Features can be add to and reused across site definitions

l New features can be activated in existing site to add functionality

l Features scoped at web, site ,web application and farm.

l Features need to be installed before they can be activated, via stsadm.exe or custom code using SharePoint API

l Once installed, a user can activate or deactivated feature in context of site or site collection

Features are composed of XML files and .aspx files

l XML in CAML

l Features have ID, name, scope

l Features are composed of elements

l Generate GUID using Visual Studio 2005

Feature Dependencies

Features can be designed with dependencies: Allows one feature to assume another feature is present Example: Feature B might depend on feature A.

l B should be written with activation dependency on A

l Activating B forces A to be activated as well

l Deactivating B results in deactivation of A

Features can be defined as hidden; this will hide the feature from users in administration pages, however it can still be activated via dependencies

Features and Site Definitions

Features add modularity to site definitions: Site definitions can include feature references, e.g. Lists, document libraries, content types, etc.

Activating Features via the UI

Feature elements can add commands to WSS 3.0 UI:

l Extensible to site settings, action actions, menus, ECB, etc.

l Performed using SiteActions menu elements with Url Action

l ECB menu associated by list type, content type or file type

Feature Site Template Associations a.k.a. Feature Stapling

l Enables you to include a specific feature as part of a site definition when you provision sites through the site definition

l Preserves original out of the box definitions

l Keeps customer environment in a supported state

l Makes it easier to manage customizations in customer environments

l Reduces development and deployment time

Examples of where SharePoint can be extended using Features (based on scope):

Farm Elements

l Item Custom Actions

l Site Settings Links

l Admin Custom Actions

Web Application elements

l Item Custom Actions

l Site Settings Links

l Admin Custom Actions

Site Elements

l Site Settings Links

l Site Web Part Definitions

l Workflow Definitions

l Site Content types

l Site columns

l Files [provisioned to root web]

l List Instances [provisioned to rootweb]

Web Elements

l List Definitions + Forms + Views

l List Instances

l List Item Events

l Item Custom Actions

l Web Admin Custom Actions

l Files

Event Handlers - Part 3: Register Event Handlers plus free Site Settings – Manage Event Handlers Add-on solution

Brian Wilson — Sun, 18 Mar 2007 21:31:00 GMT

This post is the third post of a 3 post series.

Post 1: Everything you need to know about MOSS Event Handlers

Post 2: Developer Solution Starter Kit (Building and deploying event handlers to MOSS)

Post 3: Registering Event Handlers plus Site Settings - Manage Event Handlers

In the first post, I discussed the benefits of using Event Handlers in Microsoft Office SharePoint Portal Server 2007 (MOSS).

In the second post, I discussed how to develop and deploy Event Handler solutions for Microsoft Office SharePoint Portal Server 2007 (MOSS).

In this post I will discuss the various mechanisms to attach (register) your event handler assembly to a site, list, or content type. The "Site Settings – Manage Event Handlers Add-on" solution is hosted on CodePlex. Here is the link:

Codeplex Project : http://www.codeplex.com/SPSCustomAdmin/

(If any of you are interested in getting involved, I am interested in building more Site Settings addons. Please email me at brwil at microsoft dot com if you would like to get involved in expanding this framework. I will discuss the ideas i have in more detail in a future blog post.)

Overview

So you have deployed the assembly to the farm, now what? How do I register an event in your assembly for a Site, List, or Content Type?

I will describe three ways to deploy your assembly’s events.

1) Manage EventReceivers via Code

2) Deploy event handlers using the Feature framework of MOSS 2007

3) A cool custom Site Settings Application I built to manage (view, add, edit and delete) event handlers.

Managing EventReceivers via Code

The site (SPWeb) object, the list (SPList) object and the Content Type (SPContentType) object expose a collection called EventReceivers based on the SPEventReceiverDefinitionCollection class.

This collection maintains a set of SPEventReceiverDefinition objects (events) attached to a site, list or content type.

Adding Event Handlers (SPEventReceiverDefinition)

This class provides an “Add” method to attach a new SPEventReceiverDefinition (We created and deployed these to MOSS in Post 1 and 2.) The Add method asks for three bits of information:

· SPEventReceiverType: This tells SharePoint the type of event receiver we are adding to the EventReceiver collection.

· Assembly name: The name of the assembly. E.g. “Litwarehandlers, Version 1.0.0.0, Culture=neutral, PublicKeyToken=a6ab42c509981682”

· Class name: The name of the class. E.g. “Litwarehandlers.SiteHandlerClass”

(An easy way to get this information is to use our trusty old friend, Lutz Roeder’s Reflector application. Simply reflect the class and copy and paste the information you need.)

Once attached, the site, list or content type will now start picking up these events and executing your assemblies code.

Modifying Sequence Numbers

Another important property you may want to set for each event you attach is the Sequence Number. The sequence number determines the order your event assemblies’ fire. This is especially important when you have created multiple assemblies that are all attached to the same Site, List or Content Type event.

To modify the Sequence Number, you need to retrieve the SPEventReceiverDefinition object from the EventReceivers collection.

· Site: site.EventReceivers

· List: list.EventReceivers

· Content Type: site.ContentTypes[content type name].EventReceivers

A suggested best practice (and only my opinion), do not use sequence numbers below 10000 as SharePoint uses event handlers extensively to run SharePoint Workflows, etc. These event handlers use Sequence Numbers, starting at 1000.

Deleting Event Handlers (SPEventReceiverDefinitions)

When removing definitions, here is what you have to do:

Site:

· Attach to the site (SPWeb)

· Lookup the SPEventReceiverDefinition object in the site.EventReceivers collection.

· Use the delete method of the SPEventReceiverDefinition object to remove it from the collection.

· Call the site.Update() method.

List:

· Attach to the site (SPWeb)

· Retrieve the list : (site.Lists[GUID or listname])

· Lookup the SPEventReceiverDefinition object in the list.EventReceivers collection.

· Use the delete method of the SPEventReceiverDefinition object to remove it from the collection.

· Call the list.Update() method.

Content Types:

· Attach to the site (SPWeb)

· Retrieve the SPContentType (site.ContentTypes[SPContentTypeId])

· Retrieve the SPEventReceiverDefinition object : (SPContentType.EventReceivers[GUID])

· Use the delete method of the SPEventReceiverDefinition object to remove it from the collection.

· Call the SPContentType.Update() method.

Managing assemblies using Features

It is possible to create a feature that deploys your event handler to the assembly.

MSDN has an example on how to achieve this: http://msdn2.microsoft.com/en-us/library/ms453149.aspx

See screenshot of the xml you need to write to deploy an event via the features framework:

Limitations:

· It is difficult to see what event handlers are installed and the sequence they are firing for a site, list or content type. To modify, requires rebuilding the feature with the correct settings.

· Using a feature, “hardcodes” the event handler to an individual list or Content Type. Each time you want to use the SAME event handler, you are forced to write another feature to register it.

In my opinion, wrapping functionality as a feature is cool, but is overkill for registering event handlers. This is my reason for building a view, add, edit and remove application via Site Settings. See below! J

Managing EventReceivers using Site Settings application assemblies

Features

The Manage Event Handler site settings application provides you with the ability to view all events that have been associated to a site, any list of that site, and all Content Types for that site.

You can add event handlers, edit the sequence numbers and delete events registrations. Once the feature is activated, it is accessible from the Site Settings of any site

Feature – Event Handler Screenshot

Site Settings Event Handlers Screenshot

Manage Event Handlers" style="WIDTH: 916px; HEIGHT: 844px" height=844 alt="Site Settings > Manage Event Handlers" src="http://blogs.msdn.com/photos/brian_wilson/images/1909625/original.aspx" width=916 mce_src="http://blogs.msdn.com/photos/brian_wilson/images/1909625/original.aspx">

View Event Hhandlers Screenshot:

Add Event handlers Screenshot:

Edit Event handlers Screenshot:

Delete Event handlers Screenshot

Firstly, download the solution deployment code and wsp file from CodePlex here, and install in your SharePoint environment. (If you pick up any issues or have feature requests, please let me know so that I can add these to future releases.)

How to install

1. Follow the steps in my previous post in the "Deploying your assembly to staging and production" section. It provides step by step instructions on how to install a wsp file.

2. Navigate to any site and open Site Settings.

3. Open “Site Features” under the Site Administration column.

4. Activate the new feature called “Manage Event Handlers”. This enables event handler management application for this site.

5. Navigate back to Site Settings. A new option is now available under the “Site Administration column” called “Manage Event Handlers”. Select this option.

Notes

I have removed the ability to edit or delete native SharePoint generated event associations as this may affect the stability of SharePoint Out-Of-The-Box functionality. Only YOUR events can be managed.

Content Types (and their associated event handlers) can only be managed via the root site of the site collection.

In case you are wondering how to go about building your own site settings applications I have posted the code on CodePlex. I am planning on building an additional site settings administration application to manage and configure site properties.

Summary

If you have any questions, add a comment and time permitting, I will try to respond as soon as possible.