C# return memory stream from OpenXML resulting to a corrupted word file

Question

I have a problem with a MemoryStream from OpenXML. I succeed with opening a Word file, changing it and downloading it through the HttpResponse if I do all the steps in a single method.

But if I try to do it in two different classes (or methods) by returning the MemoryStream, I get a corrupted word file. I thought about a flushing or buffer problem but I don't find a solution.

Here is the working code :

    public void FillTemplateOpenXmlWord(HttpResponse response)
    {
        string filePath = @"c:\template.docx";
        byte[] filebytes = File.ReadAllBytes(filePath);

        using (MemoryStream stream = new MemoryStream(filebytes))
        {
            using (WordprocessingDocument myDoc = WordprocessingDocument.Open(stream, true))
            {
                // do some changes
                ...
                myDoc.MainDocumentPart.Document.Save();
            }

            string docx = "docx";
            response.Clear();
            response.ClearHeaders();
            response.ClearContent();
            response.AddHeader("content-disposition", "attachment; filename=\"" + docx + ".docx\"");
            response.ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
            response.ContentEncoding = Encoding.GetEncoding("ISO-8859-1");
            stream.Position = 0;
            stream.CopyTo(response.OutputStream);
            response.End();
        }
    }

Here is the non-working code :

    public void OpenFile(HttpResponse response)
    {
        MemoryStream stream = this.FillTemplateOpenXmlWord();

        string docx = "docx";
        response.Clear();
        response.ClearHeaders();
        response.ClearContent();
        response.AddHeader("content-disposition", "attachment; filename=\"" + docx + ".docx\"");
        response.ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
        response.ContentEncoding = Encoding.GetEncoding("ISO-8859-1");
        stream.Position = 0;
        stream.CopyTo(response.OutputStream);
        response.End();
    }

    public MemoryStream FillTemplateOpenXmlWord()
    {
        string filePath = @"c:\template.docx";
        byte[] filebytes = File.ReadAllBytes(filePath);

        using (MemoryStream stream = new MemoryStream(filebytes))
        {
            using (WordprocessingDocument myDoc = WordprocessingDocument.Open(stream, true))
            {
                // do some changes
                ...
                myDoc.MainDocumentPart.Document.Save();
            }

            return stream;
        }
    }

Any idea ?

thank you

Answer 1

looks like stream is closing when you return. it is in a using block. wouldn't that close the memory stream as soon as the filltemplate procedure ends?