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Monday, March 05, 2007 10:07 AM Brian Wilson

Event Handlers - Part 1: Everything you need to know about Microsoft Office SharePoint Server (MOSS) Event Handlers.

This post is the first post of 3 posts.

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

Overview Today I want to talk in depth about a feature of Microsoft Office SharePoint Server

2007 (MOSS) that shows you just how extensible the SharePoint 2007 platform is!

That feature is the ability to add custom event handlers to sites, lists, items and

content types in your portal. What is a custom event handler? A custom event handler is a .Net assembly that

contains the additional business logic you need to run when the event occurs in

SharePoint.

Why did I pick this feature? Well, no portal or business application ever really lives

in isolation to your other Line of Business (LOB) applications, and shouldn't! Your

portal solution needs to be dynamic, expect change and work seamlessly with the

other systems in your environment. So, you may ask, what does this have to do

with Event Handlers?

Well, event handlers allow you to add [SOMETHING] your business needs into the

functionality of SharePoint. [SOMETHING] examples:

o Retrieve information from a database such as filling in the remaining fields

of a list based on a CustomerID (assuming you don't have an enterprise

license for BDC)

o Call a web service

o Start a workflow

o Perform list data validation

o Convert document to PDF and store in alternative list.

o Access data in another list.

The possibilities around writing custom event handlers to perform an action based

on an event in SharePoint 2007 are endless!

Event Types Here is a list of events that you can hook into:

• Microsoft.SharePoint.SPWebEventReceiver : "Site Level"

SiteDeleted Occurs after a site collection has been deleted.

SiteDeleting Occurs when a site collection is being deleted.

WebDeleted Asynchronous Afterevent that occurs after an existing Web site is

completely deleted.



• Microsoft.SharePoint.SPListEventReceiver : "List Level"

• Microsoft.SharePoint.SPItemEventReceiver : "List Item Level"

WebDeleting Synchronous before event that occurs before an existing Web site is

completely deleted.

WebMoved Asynchronous after event that occurs after an existing Web site has

been moved.

WebMoving Synchronous before event that occurs before an existing Web site has

been renamed or moved to a different parent object.

FieldAdded Occurs after a field link is added.

FieldAdding Occurs when a field link is being added to a content type.

FieldDeleted Occurs after a field has been removed from the list.

FieldDeleting Occurs when a field is in the process of being removed from the

list.

FieldUpdated Occurs after a field link has been updated

FieldUpdating Occurs when a field link is being updated

ItemAdded Asynchronous After event that occurs after a new item has been

added to its containing object.

ItemAdding Synchronous before event that occurs when a new item is added to

its containing object.

ItemAttachmentAdded Asynchronous after event that occurs after a user adds an

attachment to an item.

ItemAttachmentAdding Synchronous before event that occurs when a user adds an

attachment to an item.

ItemAttachmentDeleted Asynchronous after event that occurs when after a user removes

an attachment from an item.

ItemAttachmentDeleting

Synchronous before event that occurs when a user removes an

attachment from an item.

ItemCheckedIn Asynchronous after event that occurs after an item is checked in.

ItemCheckedOut Asynchronous after event that occurs after an item is checked out.

ItemCheckingIn Synchronous before event that occurs as a file is being checked in.

ItemCheckingOut Synchronous before event that occurs after an item is checked out.

ItemDeleted Asynchronous after event that occurs after an existing item is

completely deleted.

ItemDeleting Synchronous before event that occurs before an existing item is

completely deleted.



Asynchronous vs Synchronous Events: The "ing" and the "ed"

As you may have noticed above, there are two events raised for each type of

event. The "...ing" event occurs before the action starts and the "...ed" occurs

after the actions ends. "...ing" events occur synchronously while the "...ed" events occur asynchronously. What does this mean? Synchronous events:

• Occur before the event.

• Block the flow of code execution until your event handler completes. • Provide you with the ability to cancel the events resulting in no after event

(“...ed") being fired. Asynchronous events:

• Occur after the event. • Do not block the flow of code execution in SharePoint.

Combining Custom Event Handlers with Content Types = POWER!

Content Type is just what it sounds like: a metadata description of content that can include custom properties, a retention policy, and an associated set of workflows and business processes.

For example, a company may define a “Contract” Content Type that includes the required metadata to make it easy to find that contract later.

The “Contract” Content Type is now a metadata description definition that can be associated to lists such as Document Libraries in your SharePoint environment. Once added, you now have the ability to add and manage Contracts added to your portal.

ItemFileConverted

ItemFileMoved Occurs after a file is moved.

ItemFileMoving Occurs when a file is being moved.

ItemUncheckedOut Synchronous before event that occurs when an item is being

unchecked out.

ItemUncheckingOut Synchronous before event that occurs when an item is being

unchecked out.

ItemUpdated Asynchronous after event that occurs after an existing item is

changed, for example, when the user changes data in one or more

fields.

ItemUpdating Synchronous before event that occurs when an existing item is

changed, for example, when the user changes data in one or more

fields.



This is where Event Handlers come in: You can attach custom event handlers to a Content Type! Once attached to the Content Type definition, it picks up the events wherever you use the content type. This is extremely powerful! Why? Well, you have the ability to target individual content types across the entire site collection. For example, wherever a “Contract” Content Type is used, you could store a link in another system for each Contract created in your system, no matter what document library the contract is stored in.

Best Practices

When building custom event handlers, keep the following points in mind:

1. Security: The assembly you deploy to the Global Assembly Cache(GAC) is running with full

trust. Watch out for the following:

• Denial of Service attack: If a user uploads 10000 items to a list, what is

the effect it will have to the systems your assembly uses. • SQL Injection attack: If a user attempts to insert SQL statements into a

column of a list that your assembly uses to update a database, what

mechanisms are you using to make sure the input is valid. • Cross Site scripting attack: What is the effect of adding script to a

column that your assembly uses to update another area in SharePoint?

2. Performance:

Watch out for the following:

• Load: What burden are you placing on your web front end servers to run

the assembly each time an event occurs? Use performance counters to

determine this.

• Long Running Operations: Consider creating a custom SharePoint timer

job. Kick off/ Schedule the Timer Job from the event rather than running all

the logic inside the event. This will allow you to use the features of

SharePoint to view whether the Timer Job ran successfully.

• Sync vs Async Events: Synchronous events have to wait until your code

completes before returning the page, whereas Asynchronous events show

the page immediately.

3. Error Handling:

When using synchronous events and you decide to cancel an event, let the user

know why the event was cancelled. For example, update a Task List with a

message why it failed.

Log your errors so that you can determine what issue is occurring when your

system is in production environment.

4. Connections: Cater for external systems being down when you are trying to



connect to them. Don’t let your code / solution go belly up because you cannot

connect to a database.

5. Bulk Operations:

The MSDN documentation mentions that event handlers will not fire when bulk

operation is occurring. For example, when a new list is created, the FieldAdding

event will not fire.

Limitations of Event Handler in SharePoint

Strangely there is no “SiteAdding”, “SiteAdded” event. However, if you really need

this event you could create a “feature” to accomplish this. Features in SharePoint

have a “FeatureActivated” event, where you could perform an action on creation of

a site.

Summary Custom Event handlers are a powerful tool in your arsenal as a SharePoint

Architect/ Developer! Filed under: WSS, MOSS 2007, Event Handlers, CodePlex, Starter Kit, How To

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Comments

# Brian Wilson's Blog : Part 1: Event Handlers: Everything you need to know about Microsoft Office SharePoint Portal Server (MOSS) Event Handlers.

Monday, March 05, 2007 5:21 AM by Brian Wilson's Blog : Part 1: Event Handlers: Everything you need to know about Microsoft Office SharePoint Portal Server (MOSS) Event Handlers.

PingBack from http://blogs.msdn.com/brianwilson/archive/2007/03/05/part-1-event-handlers-everything-you-need-to-know-about-microsoft-office-sharepoint-portal-server-moss-event-handlers.aspx

# Event Handlers in SharePoint 2007

Monday, March 05, 2007 9:27 AM by Jan Tielens' Bloggings

Brian Wilson has started a nice series on event handlers in SharePoint 2007, first episode: Everything

# re: Part 1: Event Handlers: Everything you need to know about Microsoft Office SharePoint Portal Server (MOSS) Event Handlers.



Monday, March 05, 2007 9:59 AM by AndersR

Have you any experience with the ContextEvent? Its mentioned as an item level event in the SDK, but i can find zero documentation on it :-s


Tuesday, March 06, 2007 3:22 AM by MikeWal2

Can I suggest you change the name to

"Event Handlers - Part 1: Everything you need to know about Microsoft Office SharePoint Portal Server (MOSS) Event Handlers

to keep all three nicely lined up as Event Handler articles rather than as articles about Part1; Part 2 and Part3.

Mike Walsh

# Event Handlers in SharePoint 2007 Part 1

Friday, March 09, 2007 10:23 AM by SharePointKicks.com

You've been kicked (a good thing) - Trackback from SharePointKicks.com

# WSS FAQ - additions and corrections - XXXXV 4th - 11th March 2007

Sunday, March 11, 2007 4:34 AM by Mike Walsh's WSS and more

# WSS FAQ - additions and corrections - XXXXV 4th - 11th March 2007

Sunday, March 11, 2007 4:36 AM by Mike Walsh's WSS and more

# SharePoint Kaffeetasse 02

Friday, March 23, 2007 4:52 AM by SharePoint, SharePoint and stuff

Entwicklung Create a link that opens in a new window in SharePoint 2007 Event Handler Part 1: Everything


Wednesday, March 28, 2007 3:35 PM by bowerm

Come on Brian - time for part 2 by now - i know you don't have much work to do.

# Event Handlers - Part 2: Building and Deploying Event Handlers (Including Event Handler



Starter Solution Kit)

Friday, April 06, 2007 6:01 AM by Brian Wilson's Blog

This post is the second post of a 3 post series. Post 1: Everything you need to know about MOSS Event

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

Tuesday, April 10, 2007 5:41 PM by Brian Wilson's Blog

This post is the third post of a 3 post series. Post 1: Everything you need to know about MOSS Event

# re: Event Handlers - Part 1: Everything you need to know about Microsoft Office SharePoint Portal Server (MOSS) Event Handlers.

Wednesday, April 11, 2007 7:02 AM by Gary Homewood

This is a very useful article. What I'd really like, however, is an event handler at the web site level, so that I can do something whenever a Survey is added to the site. Is this possible?

# MOSS Sample : un bon exemple d'Event Handler (gestion des permissions)

Thursday, April 12, 2007 9:11 AM by The Mit's Blog

(Si vous êtes novice sur les event handler, regarder à la fin du post ) En parcourant les forums SharePoint,

# MOSS Sample : une bon exemple d'Event Handler (gestion des permissions)

Thursday, April 12, 2007 9:11 AM by The Mit's Blog

(Si vous êtes novice sur les event handler, regarder à la fin du post ) En parcourant les forums SharePoint,

# re: Event Handlers - Part 1: Everything you need to know about Microsoft Office SharePoint Server (MOSS) Event Handlers.

Friday, May 11, 2007 12:35 PM by Kurt Heyrman

I have been trying to use event handlers. I got simple examples working, but when I extend the code to call a service (WCF) or insert something in a database (ADO.NET) it seems as if my code isn't even run anymore. Any ideas?


Tuesday, May 29, 2007 4:38 AM by Leon Zandman

The hyperlink that should be pointing at part 2 of your series is pointing to part 1! Please fix it.

of 19Brian Wilson! : Event Handlers - Part 1: Everything you need to know about Microsoft...



Tuesday, June 12, 2007 10:44 AM by AnonyMoose

Hi,

This can't be EVERYTHING we need to know about MOSS event handlers because I need to know what the ContextEvent is (as AndersR also asked). The ContextEvent doesn't appear in your SPItemEventReciever lists, but this is event type definitely exists.

Have you got any info on this yet?


Thursday, June 21, 2007 8:21 PM by phani

Hi Brian,

Thanks for your article on Event Handlers. I have a typical requirement where i need to rename the file before it got uploaded to sharePoint. Ideally sharepoint does not allow files with illegal characters like # in SPS##faq.doc. I would like to remove those illegal characters so that sharepoint can accept this file as SPSfaq.doc.

I am unable to accomplish this functionality in the ItemAdding event.

I would like to hear your comments on this. If you have any better solution other event handlers like using javascript, that will also be helpful.

I appreciate if you can provide any code or reference.

phani.

# SharePoint Event Handlers, Part 2

Thursday, July 12, 2007 4:37 PM by Greg Manrodt's Blog

In my previous post, I described the current state of event handlers in MOSS and WSS v3. Also, I listed

# Document libraries, Folders & Content Types

Thursday, July 19, 2007 1:30 PM by Chris Johnson

I have been asked a few times if it is possible to associate different Content Types with different folders

# Document libraries, Folders & Content Types

Thursday, July 19, 2007 2:08 PM by Noticias externas



I have been asked a few times if it is possible to associate different Content Types with different folders


Thursday, July 26, 2007 2:59 AM by Chandler Chou

hi,

i wrote a event handler and put it into my MOSS 2007, after i run some unit test cases, i found some libraries and lists won’t fire event, following is the list of those lists:

- Translation Management Library

- Data Connection Library

- Slide Library

- Report Library

- Project Tasks

- Languages and Translators

- KPI List

Is this a bug or not?

Does event receiver support all type of libraries and lists?


Thursday, July 26, 2007 2:57 PM by SharePoint, SharePoint and stuff

Anpassung How to create your own custom wiki site definition Create a KPI List in WSS 2.0/3.0 Customizing

# SPPD075 SharePointPodcast

Friday, July 27, 2007 3:06 PM by SharePointPodcast.de

Direkter Download: SPPD-075-2007-07-27 Diesmal nur mit kurzen Shownotes Buchtipps Microsoft Office SharePoint


Friday, July 27, 2007 3:06 PM by SharePoint, SharePoint and stuff

Direkter Download: SPPD-075-2007-07-27 Diesmal nur mit kurzen Shownotes Buchtipps Microsoft



Office SharePoint


Tuesday, August 14, 2007 6:40 AM by SharePoint, SharePoint and stuff

Anpassung How to create your own custom wiki site definition Create a KPI List in WSS 2.0/3.0 Customizing


Tuesday, August 28, 2007 9:00 AM by Joe Brown

The link to part 2 points to part one??????


Monday, September 03, 2007 6:29 AM by Sagar

I am trying to get a dataset from OracleDatabase in ItemAdded event. While debugging the point of execution doesnot return back to code after the command dataadapter.fill(ds), straightway the sharepoint page comes up and there is no error or exception thrown. I am not sure abt the data whehter it is obtained in ds or not.please someone help me to solve this.


Monday, September 03, 2007 4:43 PM by tintasbarnes

I think Brian you can continue with this: "how to create a counter wich counts how many times a document is opened in Sharepoint" :D ... Actually this is my problem... so if somebody can help me with this ...

plz

[email protected]


Friday, October 12, 2007 4:01 AM by sagar

are there any events on user logged in or logged out from a SharePoint site?...i need them for showing Who's Online webpart.

Any help.Thanks.

# re: Event Handlers - Part 1: Everything you need to know about Microsoft Office SharePoint



Server (MOSS) Event Handlers.

Thursday, October 25, 2007 9:22 AM by Liz

How can I overcome the limitations of Event Handler in SharePoint (WebAdding &WebAdded).The ActivateOnDefault attribute of the feature does not apply to site collection (Site) or Web site (Web) scoped Features.

# In the event of a SharePoint Event Handler, don’t...

Wednesday, October 31, 2007 12:16 PM by Eric Legault My Eggo

In the event of an Event Handler , don’t try to do anything "fancy". Why? Because SharePoint doesn't

# Event Handlers

Sunday, November 11, 2007 2:16 PM by Cvalik's blog

Brian Wilson napisal celkom pekny 3 dielny serial. Post 1: Everything you need to know about...


Monday, November 12, 2007 7:18 AM by dattard

Your part 2 link points to part 1.

# Allez plus loin dans le déploiement de vos features

Tuesday, November 27, 2007 4:32 AM by alex#

Avec tout les posts sur codes-sources concernant le dE9;ploiement sous SharePoint, je pense que


Wednesday, January 09, 2008 8:04 PM by Mirrored Blogs

Direkter Download: SPPD-075-2007-07-27 Diesmal nur mit kurzen Shownotes Buchtipps Microsoft Office SharePoint


Friday, February 15, 2008 5:58 AM by Marco Gonçalves

I'm using WSS 3.0 anda I need to fire the ItemAdded event in a forms library, but when I submit am infopath form to that library the event is not fired.

I also tried to make a test which consisted in disable the delete item in a library but the event



ItemDeleting only works in document library, in forms library nothing works. Any idea?

# All you need to know about Event Handlers In SharePoint 2007

Tuesday, March 11, 2008 6:07 AM by SharePoint & .NET

Below is a list of events that you can hook into: · Microsoft.SharePoint.SPWebEventReceiver : "Site Level"


Friday, March 21, 2008 8:53 AM by Arkady Fedorovtsjev

Is there a link to part 2 ?

Tnx in advance


Friday, March 21, 2008 8:55 AM by Arkady Fedorovtsjev

I found it ...

The link to 2nd part is

http://blogs.msdn.com/brianwilson/archive/2007/03/18/event-handlers-part-2-building-and-deploying-event-handlers-including-event-handler-starter-solution-kit.aspx


Thursday, June 05, 2008 9:23 AM by Brajendu Kumar Das

Can you help me for the ContextEvent? As it is given in in SDK as an item level event but no description..

Thanks in Advance......


Friday, July 11, 2008 12:47 AM by Raju

the events in the user control are not firing in MOSS please give me a solution.




Thursday, July 17, 2008 7:09 PM by DEV

Hi,

I have to write an EH to handle ItemAdding event on a FormLibrary.

A workflow is attached to this From Library.

My problem is the EH is getting fired after the WF.

And I am getting null error when I try to access the filename in EH - ItemAdding .

Any help is appreciated.

Thanks,

Dev

[email protected]


Tuesday, July 22, 2008 4:27 AM by gowri sankar

hi,

while list loading i want to change certain fields text. for example changing the date format.

I would like to know is there any event like rowdatabound of asp.net gridview control.

any help is appreciated.

Regards,

Sankar.

[email protected]


Wednesday, July 23, 2008 8:03 PM by Paul Noone

Hi Brian,

Great first post. Just a heads-up that the link to Post 2 currently points to this post.

Should be: http://blogs.msdn.com/brianwilson/archive/2007/03/18/event-handlers-part-2-building-and-



deploying-event-handlers-including-event-handler-starter-solution-kit.aspx


Thursday, August 07, 2008 7:58 AM by Priyanka

Hi Brian,

Great post. I however, had a question, I have a dropdown on NewForm.aspx page of a list. I am customizing it. I wanted to place an event for SelectedIndexChanged for this drop down, and call another method to get some details and fill other boxes. How do I render event for this dropdown?

# Dostęp do obiektu sesji z SharePoint

Saturday, August 16, 2008 4:33 PM by .neting in the free world

Skoro MOSS/WSS jest aplikację Web napisaną w .NET, można by przypuszczać iż wywołanie: HttpContext .Current.Session

# Test... Test Kodu... oraz wklejenia z Office

Tuesday, August 26, 2008 8:11 PM by .neting in the free world

Test... Test Kodu... oraz wklejenia z Office

# [SharePoint開開] EventHandler 開開開開

Tuesday, September 16, 2008 2:06 AM by 晃晃晃晃

晃晃晃晃晃SharePoint晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃晃SharePoint晃


Tuesday, September 16, 2008 6:20 AM by manjunathatv

I have to track the changes made on a word content(when its opened in ms-office), for that I need to handle shortterm checkin event. but ItemCheckedIn event is fired only when its checked out in Long term Checkout. any idea on this...

thanx.


Sunday, November 02, 2008 7:40 PM by Charan

A question on 'Limitations of Event Handler in SharePoint' which you have specified in this article.



Could you please elaborate more on how to use "FeatureActivated" method to capture an event when site is created?

Thanks,

Charan


Thursday, November 06, 2008 11:15 PM by Rakesh

I have requirement. When we manage permission of the list item it should fire the event so that I can put my custom code in that even. I donot find any event for Manage Permission. Please suggest.


Thursday, November 20, 2008 2:23 AM by Dharnendra

Hi,

I am using some unsigned Project DLL (like Common,etc..) inside my event receiver class library.

When i am trying to deploy my DLL, its also ask for the deployment of 'Common' project DLL at GAC but as the project is referring some unsigned DLL ,i can' make that project to signed and so enable to put that it's in GAC.

Can i get any workaround for the above situation?

Do it possible that i not require to deploy the DLL to GAC and can work with DLL by placing only it in 'Application's Bin' folder.

Please provide me your help...its urgent

Thanks

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