MongoDb.GridFS.FindOneById returns null

Question

I'm uploading image to server with following code:

public ActionResult AttachImage(HttpPostedFileBase file)
{
   var options = new MongoGridFSCreateOptions
   {
      Id = ObjectId.GenerateNewId().ToString(),
      ContentType = file.ContentType
    };
    Context.Database.GridFS.Upload(file.InputStream, file.FileName, options);
    return RedirectToAction("Index");
}

and trying to get file like:

public ActionResult GetImage(string id)
{
   var image = Context.Database.GridFS.FindOneById(new ObjectId(id));
   if(image == null)
   {
      return HttpNotFound();
   }
   return File(image.OpenRead(), image.ContentType);
}

After upload I can see file in database, but when I'm trying to load it as

Context.Database.GridFS.FindOneById(new ObjectId(id));

I'm always geting null. Could you please suggest what I'm doing wrong?

public class DbContext
{
    public MongoDatabase Database;
    public DbContext()
    {
        var client = new MongoClient(Properties.Settings.Default.ConnectionString);
        var server = client.GetServer();
        Database = server.GetDatabase(Properties.Settings.Default.DatabaseName);
    }
}

mongocsharpdriver 2.5.0 mongo server 3.6

Answer 1

It turned out I incorrectly searched for file by Id.

Instead of

var image = Context.Database.GridFS.FindOneById(new ObjectId(id));

I should use

var image = Context.Database.GridFS.FindOneById(id);

I used code from examples for previous version of driver but in 2.5 we don't need to use

 new ObjectId(id)