<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/"><Receivers ListTemplateId="10000"><Receiver><Name>EricSunArticlesListItemEventReceiverItemAdding</Name><Type>ItemAdding</Type><Assembly>$SharePoint.Project.AssemblyFullName$</Assembly><Class>EricSunSharePointProject.ListInstances.EricSunArticlesListItemEventReceiver.EricSunArticlesListItemEventReceiver</Class><SequenceNumber>10000</SequenceNumber></Receiver><Receiver><Name>EricSunArticlesListItemEventReceiverItemUpdating</Name><Type>ItemUpdated</Type><Assembly>$SharePoint.Project.AssemblyFullName$</Assembly><Class>EricSunSharePointProject.ListInstances.EricSunArticlesListItemEventReceiver.EricSunArticlesListItemEventReceiver</Class><SequenceNumber>10000</SequenceNumber></Receiver></Receivers>
</Elements>

using System;
using System.Security.Permissions;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.Workflow;
using System.Text.RegularExpressions;namespace EricSunSharePointProject.ListInstances.EricSunArticlesListItemEventReceiver
{/// <summary>/// List Item Events/// </summary>public class EricSunArticlesListItemEventReceiver : SPItemEventReceiver{/// <summary>/// An item is being added./// </summary>public override void ItemAdding(SPItemEventProperties properties){try{if (IsTargetContentType(properties.List)){SPListItem listItem = properties.ListItem;InitAttachmentString(listItem, "EricSunArticleAttachments");InitCategoryString(listItem, "EricSunCategories", "EricSunCategoryString");}}catch (SPException ex){}}/// <summary>/// An item is being updated./// </summary>public override void ItemUpdated(SPItemEventProperties properties){try{if (IsTargetContentType(properties.List)){SPListItem listItem = properties.ListItem;InitAttachmentString(listItem, "EricSunArticleAttachments");InitCategoryString(listItem, "EricSunCategories", "EricSunCategoryString");}}catch (SPException ex){}}/// <summary>/// Judge target content type./// </summary>private bool IsTargetContentType(SPList List){bool isTargetContentType = false;if (List == null){throw new ArgumentNullException("List is null.");}SPContentTypeCollection contentTypeCollection = List.ContentTypes;foreach (SPContentType contentType in contentTypeCollection){if (contentType.Name.Equals("EricSunArticleContentType", StringComparison.Ordinal)){isTargetContentType = true;break;}}return isTargetContentType;}/// <summary>/// Initial category string from category lookup./// </summary>private void InitCategoryString(SPListItem listItem, string fromField, string toField){if (listItem == null){throw new ArgumentNullException("List item is null.");}if (listItem[fromField] == null){throw new ArgumentNullException("List field is null.");}SPFieldLookupValue categoryLookup = new SPFieldLookupValue(listItem[fromField].ToString());string[] choices = Regex.Split(categoryLookup.ToString(), ";#");string categories = string.Empty;for (int i = 1; i < choices.Length; i += 2){categories += choices[i] + ";";}listItem[toField] = categories;listItem.Update();}/// <summary>/// Initial attachment string when add attachment to item/// </summary>private void InitAttachmentString(SPListItem listItem, string toField){if (listItem == null){throw new ArgumentNullException("List item is null.");}SPAttachmentCollection attachments = listItem.Attachments;string attachmentList = string.Empty;foreach (string attachment in attachments){string name = attachment;string url = SPUrlUtility.CombineUrl(attachments.UrlPrefix, attachment);attachmentList += name + "," + url + ";";}listItem[toField] = attachmentList;listItem.Update();}}
}