Enable to execute -ed events synchronously or asynchronously in SharePoint 2010

In SharePoint 2007, -ed events are executed only asynchronously.
This causes some problems between the main thread the and sub thread. For instance, -ed event thread sometimes cannot get its own item's "afterproperties".


Using SharePoint 2010, -ed events can be executed either synchronously or asynchronously.

The two Event Receivers are as follows:

• -ing events (ItemAdding, ListAdding, etc)
• synchronously 
• -ed events (ItemAdded, ListAdded, etc)
• synchronously or asynchronously

You can write "Synchronous" in Elements.xml in SharePoint EventReciver Project in Visual Studio 2010.

<Synchronization>Synchronous</Synchronization>

Listed below are the steps for making a synchronous -ed event:

• Create project as Event Receiver.

• Choose 2 events (ItemAdding and ItemAdded).

• Write the code. I added the current thread name in ULS log in ItemAdding and ItemAdded method to see status of thread. It is also necessary to add Microsoft.SharePoint.Administration namespace.

using System;
using System.Security.Permissions;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Security;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.Workflow;
using Microsoft.SharePoint.Administration;

namespace EventReceiverProject4.EventReceiver1
{
    /// <summary>
    /// List Item Events
    /// </summary>
    public class EventReceiver1 : SPItemEventReceiver
    {
       /// <summary>
       /// An item is being added.
       /// </summary>
       public override void ItemAdding(SPItemEventProperties properties)
       {
           System.Threading.Thread.CurrentThread.Name = "Current Thread";
           string theadName = System.Threading.Thread.CurrentThread.Name;

           SPDiagnosticsService.Local.WriteTrace(0, new SPDiagnosticsCategory("ItemAdding", TraceSeverity.Unexpected, EventSeverity.Error), TraceSeverity.Unexpected, theadName, theadName);
           base.ItemAdding(properties);
       }

       /// <summary>
       /// An item was added.
       /// </summary>
       public override void ItemAdded(SPItemEventProperties properties)
       {
           string theadName = System.Threading.Thread.CurrentThread.Name;
           SPDiagnosticsService.Local.WriteTrace(0, new SPDiagnosticsCategory("ItemAdded", TraceSeverity.Unexpected, EventSeverity.Error), TraceSeverity.Unexpected, theadName, theadName);
           base.ItemAdded(properties);
       }
    }
}

The ItemAdding and ItemAdded thread names are different because ItemAdded is run asynchronously.

The results are shown here:

• ItemAdding's thread name : Current Thread
• ItemAdded's thread name : null

Next, I added <Synchronization>Synchronous</Synchronization> in Elements.xml.

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Receivers ListTemplateId="104">
      <Receiver>
        <Name>EventReceiver1ItemAdding</Name>
        <Type>ItemAdding</Type>
        <Assembly>$SharePoint.Project.AssemblyFullName$</Assembly>
        <Class>EventReceiverProject4.EventReceiver1.EventReceiver1</Class>
        <SequenceNumber>10000</SequenceNumber>
        <Synchronization>Synchronous</Synchronization>
      </Receiver>
      <Receiver>
        <Name>EventReceiver1ItemAdded</Name>
        <Type>ItemAdded</Type>
        <Assembly>$SharePoint.Project.AssemblyFullName$</Assembly>
        <Class>EventReceiverProject4.EventReceiver1.EventReceiver1</Class>
        <SequenceNumber>10000</SequenceNumber>
      </Receiver>
  </Receivers>
</Elements>

The Results are shown here: 

• ItemAdding's thread name : Current Thread
• ItemAdded's thread name : Current Thread

These are interesting results !!