Can't add handlers to certain Sitecore events

Question

I'm working with Sitecore 8 Update 2. I wanted to collect information about what is happening to the Sitecore items ( created, saved, deleted, published,... ).

In order to achieve this I went and set up multiple eventhandlers with their respective event. All sitecore events are located in the config under configuration --> sitecore -> events.

Here i was able to add handlers ( see SaveItemActions.config ) to events such as "item:added", "item:saved" and "publish:complete". These eventhandlers now point to their respective methods in my new class ( SaveItemActions.cs ).

Unfortunately i was not able to add a handler to "item:created", "item:deleted", "item:versionAdded" and "item:versionRemoved" because i end up with the following error after adding these.

Could not instantiate event handler. Type: Sitecore.Links.ItemEventHandler. Method: OnItemDeleted> (method: Sitecore.Events.Event.GetConfigSubscribers()).

But it seems like i should be able to add handlers to these events aswell as they already have handlers provided by Sitecore. For example from /sitecore/admin/showconfix.aspx:

<event name="item:deleted">
    <handler type="Sitecore.Links.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted"/>
    <handler type="Sitecore.Tasks.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted"/>
    <handler type="Sitecore.Globalization.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted"/>
    <handler type="Sitecore.Data.Fields.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted"/>
    <handler type="Sitecore.Rules.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted"/>
    <handler type="Sitecore.Caching.Placeholders.PlaceholderCacheManager, Sitecore.Kernel" method="UpdateCaches"/>
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnItemDeleted>" patch:source="SaveItemActions.config"/>
    <handler type="Sitecore.Modules.EmailCampaign.Core.RootItemEventHandler, Sitecore.EmailCampaign" method="OnRootDeleted" patch:source="Sitecore.EmailExperience.ContentManagement.config"/>
</event>

I decompiled Sitecore.Kernel.dll to look at Sitecore.Links.ItemEventHandler ( see below ) and couldn't find anything special about it.

If anyone knows what causes this or has any kind of feedback, feel free to let me know.

SaveItemActions.config

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
   <events>

  <event name="item:added">
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnItemAdded" />
  </event>

  <!-- event name="item:created">
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnItemCreated>" />
  </event-->

  <event name="item:saved">
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnItemSaved" />
  </event>

  <event name="publish:complete">
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnItemPublished" />
  </event>

  <!-- event name="item:deleted">
    <handler type="Sitecore.Links.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted>" />
  </event-->

  <!-- event name="item:versionAdded">
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnVersionAdded>" />
  </event-->

  <!-- event name="item:versionRemoved">
    <handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnVersionRemoved>" />
  </event-->

  </events>
 </sitecore>
</configuration>

SaveItemActions.cs

using Sitecore.Data.Items;
using Sitecore.Events;
using Sitecore.Pipelines.Save;
using Sitecore.Publishing.Pipelines.PublishItem;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace be.absi.kbs.web.Helpers.Processors
{
    public class SaveItemActions 
    {
        public void OnItemSaved(object sender, EventArgs args)
        {
            // Extract the item from the event Arguments
            Item savedItem = Event.ExtractParameter(args, 0) as Item;
        }

        public void OnItemAdded(object sender, EventArgs args)
        {

        }

        public void OnItemCreated(object sender, EventArgs args)
        {

        }

        public void OnItemPublished(object sender, EventArgs args)
        {

        }

        public void OnItemDeleted(object sender, EventArgs args)
        {

        }

        public void OnVersionAdded(object sender, EventArgs args)
        {

        }

        public void OnVersionRemoved(object sender, EventArgs args)
        {

        }
    }
}

ItemEventHandler.cs

namespace Sitecore.Links
{
    public class ItemEventHandler
    {
        /*
        Bunch of other methods....
        */

        protected void OnItemDeleted(object sender, EventArgs args)
        {
            if (args == null)
            {
                return;
            }
            if (!Settings.LinkDatabase.UpdateDuringPublish && PublishHelper.IsPublishing())
            {
                return;
            }
            Item item = Event.ExtractParameter(args, 0) as Item;
            Assert.IsNotNull(item, "No item in parameters");
            LinkDatabase linkDatabase = ItemEventHandler.LinkDatabase;
            if (linkDatabase != null)
            {
                linkDatabase.RemoveReferences(item);
            }
        }
    }
}

Answer 1

All your code is ok. It's exactly how it's supposed to be written.

The only problem are typos in your configuration. You have extra > characters in method attributes for 3 of your handlers (e.g. method="OnItemDeleted>"):

<handler type="Sitecore.Links.ItemEventHandler, Sitecore.Kernel" method="OnItemDeleted>" />
<handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnVersionAdded>" />
<handler type="be.absi.kbs.web.Helpers.Processors.SaveItemActions, be.absi.kbs.web" method="OnVersionRemoved>" />