"File not found" when attaching file to list item

Question

I'm trying to write a section of code that lets users attach files to list items. The goal is to allow any user to be on the SP site and upload any "legal" file from their machine or shared drives to the site, where they are attached to the list item. I'm able to attach files this way when I RDP to the server and run it there but it doesn't work on any clients. Before I added the second "if" condition I was getting File Not Found exceptions with the exact path listed in the error, where the file is.

Markup (can't get it to show without the pre tag...please ignore it):

<pre>
<asp:FileUpload runat="server" ID="inputFile" />
<asp:Button runat="server" ID="btnAddDocument" OnClick="btnAddDocument_Click" Text="Upload" />
</pre>

Code:

    protected void btnAddDocument_Click(object sender, EventArgs e)
    {
        try
        {
            if (inputFile.PostedFile.FileName == "" || !File.Exists(inputFile.PostedFile.FileName))
            {
                lblError.Text = "No file selected or file not found";
                lblError.Visible = true;
                return;
            }

More code follows but the second condition is never satisfied. PLEASE...What am I doing wrong?

Remember, it works fine on the server.

Thanks!

Answer 1

Have a look at this solution, runs on client side instead of server side but seems like what you are looking for:

Upload list item attachment using JSOM

    function processUpload(fileInput, listTitle, itemId,success,error) {
        var reader = new FileReader();
        reader.onload = function (result) {
            var fileContent = new Uint8Array(result.target.result);
            performAttachmentUpload(listTitle, fileInput.name, itemId, fileContent,success,error);
        };
        reader.readAsArrayBuffer(fileInput);
    }


    function performAttachmentUpload(listTitle, fileName, itemId, fileContent,success,error) {

        ensureAttachmentFolder(listTitle,itemId, 
           function(folder){
               var attachmentFolderUrl = folder.get_serverRelativeUrl();
               uploadFile(attachmentFolderUrl,fileName,fileContent,success,error);
           },
           error);
    }


    function ensureAttachmentFolder(listTitle,itemId, success,error)
    {
          var ctx = SP.ClientContext.get_current();
          var web = ctx.get_web();
          var list = web.get_lists().getByTitle(listTitle);
          ctx.load(list,'RootFolder');
          var item = list.getItemById(itemId);
          ctx.load(item);
          ctx.executeQueryAsync(
            function() {
                var attachmentsFolder;
                if(!item.get_fieldValues()['Attachments']) { /* Attachments folder exists? */
                   var attachmentRootFolderUrl = String.format('{0}/Attachments',list.get_rootFolder().get_serverRelativeUrl()); 
                   var attachmentsRootFolder = ctx.get_web().getFolderByServerRelativeUrl(attachmentRootFolderUrl);
                   //Note: Here is a tricky part. 
                   //Since SharePoint prevents the creation of folder with name that corresponds to item id, we are going to:   
                   //1)create a folder with name in the following format '_<itemid>'
                   //2)rename a folder from '_<itemid>'' into '<itemid>'
                   //This allow to bypass the limitation of creating attachment folders
                   attachmentsFolder = attachmentsRootFolder.get_folders().add('_' + itemId);
                   attachmentsFolder.moveTo(attachmentRootFolderUrl + '/' + itemId);
                   ctx.load(attachmentsFolder);
                }
                else {
                   var attachmentFolderUrl = String.format('{0}/Attachments/{1}',list.get_rootFolder().get_serverRelativeUrl(),itemId); 
                   attachmentsFolder = ctx.get_web().getFolderByServerRelativeUrl(attachmentFolderUrl);
                   ctx.load(attachmentsFolder);
                }         
                ctx.executeQueryAsync(
                     function() {
                         success(attachmentsFolder); 
                     },
                     error);
            },
            error);
    }


    function uploadFile(folderUrl,fileName,fileContent,success,error)
    {
         var ctx = SP.ClientContext.get_current();
         var folder = ctx.get_web().getFolderByServerRelativeUrl(folderUrl);
         var encContent = new SP.Base64EncodedByteArray(); 
         for (var b = 0; b < fileContent.length; b++) {
             encContent.append(fileContent[b]);
         }
         var createInfo = new SP.FileCreationInformation();
         createInfo.set_content(encContent); 
         createInfo.set_url(fileName);
         folder.get_files().add(createInfo);
         ctx.executeQueryAsync(success,error);
    }

Usage

    var listTitle = 'Contacts';
    var itemId = 1;
    var fileInput = document.getElementById("customFileUploadControl");
    var file = fileInput.files[0];
    processUpload(file,  listTitle, itemId,
      function(){
         console.log('Attachment file has been uploaded');  
      }, 
      function(sender,args){
         console.log(args.get_message());
      });

Credit for the code goes to >> Vadim Gremyachev as per the link above! Hope this helps you or future folks.

Thanks.

SG.

Answer 2

In case anyone faces this in JavaScript as well.. this could highly be related to the "Attachments" folder for that list being not created yet. If you manually attach a file to any list item then delete it, this will create the Attachments folder and most likely your error will go away.