OpenXML PowerTools: is it possible to write an Excel spreadsheet to a .Net MemoryStream?

Question

I'm creating an Excel spreadsheet programmatically with PowerTools.

I installed PowerTools 4.5.3.2 in my C#/ASP.Net Core project with Nuget. The project also uses DocumentFormat.OpenXml v2.9.1.

I can generate the spreadsheet OK.

BUT...

I would like to pass the completed spreadsheet back to the user as a.Net MemoryStream.

I've pored over the PowerTools documentation and sample programs on https://github.com/OfficeDev/Open-Xml-PowerTools .

But for the life of me, I haven't seen any way to have PowerTools give me the generated data as a MemoryStream. Or, for that matter, any way to make PowerTools use a MemoryStream I pass in to it.

Q: Any suggestions?

NOTE

All I want to do is:

1. My ASP.Net web controller calls a function that generates an.xlsx spreadsheet from scratch.

2. The function uses OpenXML PowerTools (because that seems the most straightforward way to include a Pivot Table in the.xlsx)

3. Once the function returns, the controller needs to return the.xlsx back to the web client as an Asp.Net Core FileStreamResult object.

In other words, all I want to do is go from 2 (working) to 3 (that's where I'm stuck). I can't seem to "convert" the successfully created spreadsheet into a MVC FileStreamResult compatible object for the controller to pass back to the caller.

Help!

Answer 1

No, it doesn't appear that OpenXml PowerTools will let you write out to anything but an actual disk file.

So I used a temp file, then converted it to a byte[] array to pass back to the caller:

using (OpenXmlMemoryStreamDocument streamDoc = OpenXmlMemoryStreamDocument.CreateSpreadsheetDocument())
{
    doc = streamDoc.GetSpreadsheetDocument();
    ms = new MemorySpreadsheet();
    ...
    string tmpFile = System.IO.Path.GetTempFileName();
    streamDoc.GetModifiedSmlDocument().SaveAs(tmpFile);
    byte[] fileBytes = System.IO.File.ReadAllBytes(tmpFile);
    return fileBytes;

PS: I never did solve this problem: OpenXML SpreadsheetDocument SaveAs() giving file-in-use error

I ultimately gave up on PowerTools and went back to an all-OpenXml solution.