How to get unique id of file attachment CSOM SharePoint 2013 OnPremise

Question

Hi,
I need to get the unique id of the list attachment. For the document library, I am able to get it via "ListItemAllFields" but I guess it can't work that same way for list attachment. Any alternatives are available. I am targeting SharePoint 2013.

Answer 1

Hi @ASR ,

Per my test, we are not able to get unique id of attachment. But we could get the item id by the following PowerShell commands.

PowerShell Commands:

$web = Get-SPWeb -Identity http://xxx/sites/xxx  
$list = $web.Lists["yourlistname"]  
foreach ($item in $list.Items)  
{  
$attachmentCollection = $item.Attachments  
$folder = $web.GetFolder($attachmentCollection.UrlPrefix);  
foreach ($file in $folder.Files)  
{  
Write-Host $item.Id  
}  
}  

---

If an Answer is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

I don't think you can get the unique id for the list attachments but you can get item id for the attachments. try with the below code.

using Microsoft.SharePoint.Client;
using NLog;
using System;
using System.IO;
using System.Net;

namespace SiteActions.Task
{
  class Program
  {
  //You can get NLog from NuGet
  //http://www.nuget.org/packages/nlog
  private static Logger logger = LogManager.GetCurrentClassLogger();

  static void Main(string[] args)
  {
    try
    {
    int startListID;
    Console.WriteLine("Enter Starting List ID");
    if (!Int32.TryParse(Console.ReadLine(), out startListID))
    {
      Console.WriteLine("Invalid ID");
      Console.WriteLine("Press any key to exit...");
      Console.ReadKey();
      return;
    }

    String siteUrl = "http://siteaction.net/sites/teamsite";
    String listName = "SharePoint List Name";
    NetworkCredential credentials =
                new NetworkCredential("username", "password", "domain");

    using (ClientContext clientContext = new ClientContext(siteUrl))
    {
       Console.WriteLine("Started Attachment Download " + siteUrl);
       logger.Info("Started Attachment Download" + siteUrl);
       clientContext.Credentials = credentials;

       //Get the Site Collection
       Site oSite = clientContext.Site;
       clientContext.Load(oSite);
       clientContext.ExecuteQuery();

       // Get the Web
       Web oWeb = clientContext.Web;
       clientContext.Load(oWeb);
       clientContext.ExecuteQuery();

       CamlQuery query = new CamlQuery();
       query.ViewXml = @"";

       List oList = clientContext.Web.Lists.GetByTitle(listName);
       clientContext.Load(oList);
       clientContext.ExecuteQuery();

       ListItemCollection items = oList.GetItems(query);
       clientContext.Load(items);
       clientContext.ExecuteQuery();

       foreach (ListItem listItem in items)
       {
          if (Int32.Parse(listItem["ID"].ToString()) >= startListID ){

          Console.WriteLine("Process Attachments for ID " +
                listItem["ID"].ToString());

          Folder folder =
                oWeb.GetFolderByServerRelativeUrl(oSite.Url +
                "/Lists/"+listName+/Attachments/" +
                listItem["ID"]);

          clientContext.Load(folder);

          try
          {
             clientContext.ExecuteQuery();
          }
          catch (ServerException ex)
          {
             logger.Info(ex.Message);
             Console.WriteLine(ex.Message);
             logger.Info("No Attachment for ID " + listItem["ID"].ToString());
             Console.WriteLine("No Attachment for ID " + listItem["ID"].ToString());
          }

          FileCollection attachments = folder.Files;
          clientContext.Load(attachments);
          clientContext.ExecuteQuery();

          foreach (Microsoft.SharePoint.Client.File oFile in folder.Files)
          {
             logger.Info("Found Attachment for ID " +
                   listItem["ID"].ToString());

             Console.WriteLine("Found Attachment for ID " +
                   listItem["ID"].ToString());

             FileInfo myFileinfo = new FileInfo(oFile.Name);
             WebClient client1 = new WebClient();
             client1.Credentials = credentials;

             logger.Info("Downloading " +
                   oFile.ServerRelativeUrl);

             Console.WriteLine("Downloading " +
                   oFile.ServerRelativeUrl);

             byte[] fileContents =
                   client1.DownloadData("http://siteaction.net" +
                   oFile.ServerRelativeUrl);

             FileStream fStream = new FileStream(@"C:Temp" +
                   oFile.Name, FileMode.Create);

             fStream.Write(fileContents, 0, fileContents.Length);
             fStream.Close();
          }
        }
      }
    }
    }
    catch (Exception e)
    {
      logger.ErrorException(e.Message, e);
      logger.Error(e.StackTrace);
      Console.WriteLine(e.Message);
      Console.WriteLine(e.StackTrace);
    }
    }
  }
}

Ref: https://social.technet.microsoft.com/Forums/office/en-US/3881057d-6a43-4f07-8387-23d6a6dd9648/sharepoint-list-items-get-attachments-c-console-app?forum=sharepointgeneral

Thanks & Regards,
Sharath Aluri