File name is getting changed when set 'FileLeafRef' while creating file in CSOM

Question

Hello,

I have application where I am creating file on SharePoint Doc lib using CSOM. For normal file (a.txt where name exist for file), code works fine. However when file has no extension(e.g. ".abc",".1") then its working differently, after file upload the final file name is ".abc.abc" instead of ".abc". In code I am setting "FileLeafRef" due to some requirement. Why this is working different in case file has no extension? and how to solve it?

Sample Code:

var siteCollUrl = "<SiteCollURL>";

            using (ClientContext clientContext = new ClientContext(siteCollUrl))
            {                
                clientContext.Credentials = new SharePointOnlineCredentials("username", "password as secure string");

                var web = clientContext.Web;
                var site = clientContext.Site;
                clientContext.Load(web, w => w.Webs);
                clientContext.ExecuteQuery();

                var list=web.Lists.GetByTitle("doc lib 5");              

                try
                {
                    var uploadFilePath = @"C:\Users\firstname.lastname\Desktop\.1";
                    var fileCreationInfo = new FileCreationInformation
                    {
                        Content = System.IO.File.ReadAllBytes(uploadFilePath),
                        Overwrite = true,
                        Url = Path.GetFileName(uploadFilePath)
                    };

                    var destFile = list.RootFolder.Files.Add(fileCreationInfo);
                    //Due to some other requirement I need to set FileLeafRef to the same file name.
                    destFile.ListItemAllFields["FileLeafRef"] = Path.GetFileName(uploadFilePath);
                    destFile.ListItemAllFields.Update();
                    clientContext.ExecuteQuery();
                }
                catch(Exception ex)
                {
                }
            }

Output:

Thanks in advance!

Yuvraj.

Answer 1

Hi @Yuvraj Patil

When uploading a file without an extension using the SharePoint CSOM (Client Object Model), you may experience issues with SharePoint's behavior of appending the default extension to the file name. To work around this issue, you can use a workaround by temporarily adding a dummy extension during the upload and then removing it after the upload.

Here's how to upload a file without an extension using CSOM:

（This is just a code template, and the code needs to be modified according to your scenario）

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

class Program
{
    static void Main(string[] args)
    {
        string siteUrl = "https://yourtenant.sharepoint.com/sites/yoursite";
        string libraryName = "Documents";
        string uploadFilePath = @"C:\Path\To\Your\File\file_without_extension";

        using (ClientContext context = new ClientContext(siteUrl))
        {
            context.Credentials = new SharePointOnlineCredentials("username", "password");

            Web web = context.Web;
            context.Load(web, w => w.Lists);
            context.ExecuteQuery();

            List library = web.Lists.GetByTitle(libraryName);

            string fileName = Path.GetFileName(uploadFilePath);
            string dummyExtension = ".tmp";

            // Add dummy extension if file has no extension
            if (!Path.HasExtension(fileName))
            {
                fileName += dummyExtension;
            }

            FileCreationInformation fileInfo = new FileCreationInformation
            {
                Content = File.ReadAllBytes(uploadFilePath),
                Overwrite = true,
                Url = fileName
            };

            Microsoft.SharePoint.Client.File newFile = library.RootFolder.Files.Add(fileInfo);
            context.ExecuteQuery();

            // Remove dummy extension from URL if added
            if (!Path.HasExtension(fileName) && newFile.Exists)
            {
                string updatedFileName = Path.ChangeExtension(fileName, null); // Remove the dummy extension
                newFile.MoveTo(updatedFileName, MoveOperations.Overwrite);
                context.ExecuteQuery();
            }

            Console.WriteLine("File uploaded successfully.");
        }
    }
}

Here is a link for your reference:

https://stackoverflow.com/questions/29812845/c-sharp-upload-file-with-no-extension

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