Sharepoint 列表ItemAdding事件判断文件类型、获取当前上传的文件

 using System;
 using System.Security.Permissions;
 using Microsoft.SharePoint;
 using Microsoft.SharePoint.Security;
 using Microsoft.SharePoint.Utilities;
 using Microsoft.SharePoint.Workflow;
 using System.Web;
 using System.IO;

 namespace TestSharePointProject.DocEvent
 {
     /// <summary>
     /// List Item Events
     /// </summary>
     public class DocEvent : SPItemEventReceiver
     {
         HttpContext currentContext;
         public DocEvent()
         {
             currentContext = HttpContext.Current;
         }

        /// <summary>
        /// An item is being added.
        /// </summary>
         public override void ItemAdding(SPItemEventProperties properties)
         {
             //将上载的文件URL按.分为两部分:URL和文件类型
             string[] fileUrl = properties.BeforeUrl.Split('.');
             if (fileUrl.Length == )
             {
                 properties.ErrorMessage = "文件类型不合法！";
                 properties.Cancel = true;
             }
             else
             {
                 //获取上载的文件类型
                 string postFix = fileUrl[fileUrl.Length - ].ToLower();
                 if (!postFix.Contains("xlsx") && !postFix.Contains("xls"))
                 {
                     properties.ErrorMessage = "请选择上传Excel文件！";
                     properties.Cancel = true;
                 }
                 else {
                     if (currentContext != null)
                     {
                         if (currentContext.Request.Files.Count > )
                         {
                             //获取Item中被上传的所有文件
                             for (int i = ; i < currentContext.Request.Files.Count; i++)
                             {
                                 if (!string.IsNullOrEmpty(currentContext.Request.Files[i].FileName))
                                 {
                                     FileStream file = null;
                                     string path = currentContext.Request.Files[i].FileName.ToString();

                                     // Read the file. This appears to be the offending line
                                     file = File.OpenRead(path);
                                     byte[] Content = new byte[file.Length];
                                     file.Read(Content, , (int)file.Length);
                                     file.Close();
                                     file.Dispose();
                                     //itemToAdd.Attachments.Add(currentContext.Request.Files[i].FileName, Content);
                                 }
                             }
                         }
                     }
                 }
             }
         }

        /// <summary>
        /// An item is being updated.
        /// </summary>
        public override void ItemUpdating(SPItemEventProperties properties)
        {
            base.ItemUpdating(properties);
        }

     }
 }