I'm confused as hell with all the bazillion ways to read/write/create excel files. VSTO, OLEDB, etc, but they all seem to have the requirement that office must be installed.
Here is my situation: I need to develop an app which will take an excel file as input, do some calculations and create a new excel file which will basically be a modification of the first excel file. All with the constraint that the machine that runs this may not have office installed. (Don't ask why...)
I need to support all excel formats. The only saving grace is that the formats spreadsheets themselves are really simple. Just a bunch of columns and values, nothing fancy. And unfortunately no CSV as the end user might not even know what a CSV file is.