I'm trying to use the GridFS capability of the NoRM driver, but have run
into a strange problem.

I have code (an ASP.NET site), that when a file is selected, the file is
uploaded and put into a Mondo database, using NoRM and GridFS. The first
problem where the file wasn't actually stored in the database was fixed by
the post:
https://groups.google.com/d/msg/norm-mongodb/nzLXGyYwNnA/Ylf9oz-8ogkJ

The upload code is:
protected void btnUpload_Click(object sender, EventArgs e)
        {
            if (FileUpload1.HasFile)
            {
                    // opens the database and will create the new database
if it does not exist
                    using (var server =
Mongo.Create("mongodb://server/TestDB"))
                    {
                        // gets your class object collection
                        var collection = server.GetCollection<Record>();

                        Record newRecord = new Record();                    

                        var fs = FileUpload1.FileBytes; // gets the file
your uploading

                            var file = new GridFile(); // creates a new
mongo file object
                            var fileCollection = server.Database.Files();
//gets the collection of files in the database

                        // set the file properties
                            file.FileName = FileUpload1.FileName;
                            file.Content= fs; // the content of the file
                            file.ContentType = "application/pdf";
                            fileCollection.Save(file); // uploads to the
database
                            newRecord.file_id = file.Id; // gets the id of
the file that was just uploaded

                        // fill in the rest of the class proprties
                            newRecord.filename = FileUpload1.FileName;
                            newRecord.introDesc = txtIntro.Text;
                            newRecord.category = "category1";
                            newRecord.category2 = "category2";
                            newRecord.category3 = "category3";
                            newRecord.dateAdded = DateTime.Today;
                            newRecord.status = "A";
                            newRecord.paid = "yes";
                            newRecord.teaser = txtTeaser.Text;
                            newRecord.title = FileUpload1.FileName;
                            collection.Save(newRecord);

                            txtIntro.Text = "";
                            txtTeaser.Text = "";

                    }
                    lblMsg.Text = "File was uploaded";

            }

That seems to work fine, I see the entry in the database, both the files
collection and the chunks.  Now I have code that, given some criteria, will
retrieve the file and stream it to the web page:

        public void showPDF()
        {
            using (var server = Mongo.Create("mongodb://server/TestDB"))
            {
                var collection = server.GetCollection<Record>();
                var q = (from r in collection.AsQueryable()
                         where r.filename == pdfFile
                         select r).FirstOrDefault();                        

                var gridFS = server.Database.Files();// gets the files
collection
                //var file = gridFS.FindOne(new{ filename= pdfFile});
                var file = gridFS.FindOne(new { _id = q.file_id });

                var contents = file.Content.ToArray();              

                Response.Clear();
                Response.AddHeader("Content-Length",
contents.Length.ToString());
                Response.ContentType = file.ContentType;
                Response.AppendHeader("Content-Disposition", "attachment;
filename= " + pdfFile);

                // Write the memory stream containing the file directly to
                //the Response object that gets sent to the client
               Response.OutputStream.Write(contents, 0,
Convert.ToInt32(contents.Length));
                // Must end response because the rest of the pages html code
will
                //add to the file that is trying to open
                Response.End();
                HttpContext.Current.ApplicationInstance.CompleteRequest();
            }
        }

And that works, the PDF will show/be download... the first time. From there
after, even though the file is in the database, examining the file.Content
shows the size is 0

Has anyone used the GridFS and run into this problem, the second and
subsequent queries return an empty content?

Thanks.