Upload & Retrieve SharePoint attachments using Web Services (C#)

I did a lot of research to retrieve/ upload list item attachments using Client object model but found no solutions. The alternative method is Web services. This method returns the result in the form of XML Node. 

First to know about SharePoint Web Services please refer this. 

In order to connect to the web service first add a web reference to your Visual Studio project. Refer this

Here is the sample code which works absolutely.

Adding attachment to SharePoint list item

       public string AddingAttachments(string Url, string username, string password, string DomainName, int itemID, string attachFile, string ListName)

       {

           try

           {

               string attacnameName = "";

               byte[] contents;

               System.Net.NetworkCredential NC = new System.Net.NetworkCredential(username, password, DomainName);

               LService = new SharePointSvce.Lists();

               LService.Url = Url + "/_vti_bin/Lists.asmx";

               LService.Credentials = NC;

               System.IO.FileStream fStream = System.IO.File.OpenRead(attachFile);

               attacnameName = fStream.Name.Substring(3);

               contents = new byte[fStream.Length];

               fStream.Read(contents, 0, (int)fStream.Length);

               fStream.Close();

               try

               {

                   string addAttach = LService.AddAttachment(ListName, itemID.ToString(), attacnameName, contents);

               }

               catch (System.Web.Services.Protocols.SoapException ex)

               {

                   return ("Message:\n" + ex.Message + "\nDetail:\n" + ex.Detail.InnerText + "\nStackTrace:\n" + ex.StackTrace);

               }

           }

           catch (Exception ex)

           {

               return ex.Message;

           }

           return "";

       }

Retrieve attachment Details from SharePoint list item

public DataTable GetAvilableAttachmentsDetails(string Url, string username, string password, string DomainName, string SiteName, int taskID, string attachFile, string ListNAme)

       {

           try

           {

//Create table

              DataTable  dtAttachment = new DataTable();

              dtAttachment.Columns.Add("Name", typeof(string));

              dtAttachment.Columns.Add("SourceURL", typeof(string));

               System.Net.NetworkCredential NC = new System.Net.NetworkCredential(username, password, DomainName);

               LService = new SharePointSvce.Lists();

               LService.Url = currentURL + "/_vti_bin/Lists.asmx";

               LService.Credentials = NC;

               DataSet ds = new DataSet();

               XmlNode ndAttach = LService.GetAttachmentCollection(ListNAme, taskID.ToString());

               using (XmlNodeReader reader = new XmlNodeReader(ndAttach))

               {

                   ds.ReadXml(reader);

               }

               if (ds != null && ds.Tables.Count > 0 && ds.Tables[0] != null && ds.Tables[0].Rows.Count > 0)

               {

                   for (int i = 0; i <= ds.Tables[0].Rows.Count - 1; i++)

                   {

                       string sourceUrl = Convert.ToString(ds.Tables[0].Rows[i][0]);

                       int strLastIndx = sourceUrl.LastIndexOf(@"/");

                       string FileName = sourceUrl.Substring(strLastIndx + 1);

                       DataRow dr = dtAttachment.NewRow();

                       dr["SourceURL"] = sourceUrl;

                       dr["Name"] = FileName;

                       dtAttachment.Rows.Add(dr);

                   }

               }

           }

           catch (Exception)

           {

               return null;

           }

           return dtAttachment;

       }

Download attachment from SharePoint list item

public string DownloadAttachment(string Url, string username, string password, string DomainName, string SiteName, int taskID, string attachFile, string ListNAme, string SourceURL, string SavefilePath)

       {

           try

           {

               System.Net.NetworkCredential NC = new System.Net.NetworkCredential(username, password, DomainName);

               LService = new SharePointSvce.Lists();

               LService.Url = currentURL + "/_vti_bin/Lists.asmx";

               LService.Credentials = NC;

               using (WebClient client = new WebClient())

               {

                   client.UseDefaultCredentials = false;

                   client.Credentials = new NetworkCredential(username, password);

                   byte[] response = client.DownloadData(SourceURL);

                   int strLastIndx = SourceURL.LastIndexOf(@"/");

                   string FileName = SourceURL.Substring(strLastIndx + 1);

                   System.IO.FileStream fstream = System.IO.File.Create(@SavefilePath + "\\" + FileName);

                   fstream.Write(response, 0, response.Length);

                   fstream.Close();

                   return "";

               }

           }

           catch (Exception ex)

           {

               return ex.Message;

           }

       }  

 Reference : http://msdn.microsoft.com/en-us/library/lists.lists.addattachment%28v=office.12%29.aspx
                  http://www.naumanahmed.com/2012/03/sharepoint-web-services-and-dataset-how.html