creating a read/write document in memory stream

I'm creating an excel doc usi开发者_JS百科ng npoi. Using aspnet mvc's fileContentResult the output xls doc is readonly. When writing a file to stream is it possible to ensure the file has read/write capabilities.

Presumably fileContentResult has the file stored at some temporary location. If it let you write to it, your changes would eventually get lost.

Can you just copy it to a location of your choice and then make changes to it there?