0215: SP Event Handler

• Asynchronous vs Synchronous Events: The "ing" and the "ed"
  • Asynchronous : Occour after event
  • Synchronous :” Occour before event
• Microsoft.SharePoint.SPWebEventReceiver : "Site Level"
  • 

    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.

• Microsoft.SharePoint.SPListEventReceiver : "List Level"
  • 
• Microsoft.SharePoint.SPItemEventReceiver : "List Item  Level:”
  • 
• Bulk operations In SP
  • 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.
• Deploy event handler
  • 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

 

Example to Add an itemadded event handler

• Create a empty sharepoint project named SetDocFieldsLib and select GAC deployment option(need to install Sharepoint developer Tools 9.0)
• Add SetDocFields.cs to project :

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SharePoint;

namespace SetDocFieldsLib
{

public class SetDocFields : SPItemEventReceiver
    {
        // Name of hidden item that contains default properties
        const string DEFAULT_FILE_TITLE = "[defaults]";

        // local varialble to contain data passed in from SharePoint
        private SPItemEventProperties  _properties;

        // Method called AFTER a new item has been added
        public override void ItemAdded(SPItemEventProperties properties)
        {
            base.ItemAdded(properties);
            _properties = properties;

            // Run under system account
            SPSecurity.RunWithElevatedPrivileges(setFields);
        }

        private void setFields()
        {
            // Step 1: Get a handle to the item that raised the event
            SPListItem item = _properties.ListItem;

            // Step 2: Get a handle to folder containing the
            // document just uploaded
            SPFolder folder = null;
            try
            {
                if (item.File.ParentFolder != null)
                {
                    folder = item.File.ParentFolder;
                }
                else
                {
                    folder = item.ParentList.RootFolder;
                }
            }
            catch (Exception ex)
            {
                // No op
            }

            // Step 3: Assuming a folder was found (which
            // should be in all cases, find the associated
            // [defaults] document.
            if (folder != null)
            {
                SPFileCollection files = folder.Files;
                string client = "";
                string matter = "";

                // Step 4: Find the document containing defaults, and
                // use its "Client" and "Matter" values for
                // new document
                foreach (SPFile file in files)
                {
                    if (file.Title.ToLower() == DEFAULT_FILE_TITLE)
                    {
                        client = file.Item["Client"].ToString();
                        matter = file.Item["Matter"].ToString();
                        break;
                    }
                }
                item["Client"] = client;
                item["Matter"] = matter;

                // Step 5: Save changes without updating the
                // MODIFIED, MODIFIED BY fields
                item.SystemUpdate(false);
            }
        }
    }

• Deploy to gac by clicking deploy in VS 
• Create a console program named InstallEventHandlertext
• Add sharepoint.dll reference
• Add program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint;

namespace InstallEventHandlertext
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SPSite site = new SPSite("http://dayang-49u5xli7:6666/");//指定网站

                SPWeb web = site.OpenWeb();

                SPList list = web.Lists["List Docs"];//指定List

               // list.EventReceivers.Add(SPEventReceiverType.ItemDeleting, "EventHandlerText, Version=1.0.0.0, Culture=neutral, PublicKeyToken=cf7ff21d37419004", "EventHandlerText.ItemLogEvent");//添加Event Handler

                list.EventReceivers.Add(SPEventReceiverType.ItemAdded, "SetDocFieldsLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=0baa325f9c0cba8f", "SetDocFieldsLib.SetDocFields");//添加Event Handler

                Console.WriteLine("发布完成");

                Console.ReadLine();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                Console.ReadLine();
            }

        }
    }
}

• Open reflector to get public token value  and modify it in program.cs
• Run the console program

Debug eventhandler

• set breakpoint
• attach wswp.exe process
• In SP, execute changes to trigger event .