In one of our ASP.NET applications in C#, we take a certain data collection (SubSonic collection) and export it to Excel. We also want to import Excel files in a specific format. I'm looking for a library I can use for this purpose.
Requirements:
- Excel 2007 files (Does Excel 2003 support over 64k rows? I need more than that.)
- Does not require Excel on the server
- Takes a typed collection and, if it can, tries to put numeric fields as numeric in Excel.
- Works well with large files (100k to 10M) - fast enough.
- Doesn't crash when exporting GUIDs!
- Does not cost a crapload of money (no enterprise library like aspose). Free is always great, but can be a commercial library.
What library do you recommend? Have you used it for large quantities of data? Are there other solutions?
Right now, I am using a simple tool that generates HTML that is loaded by Excel later on, but I am losing some capabilities, plus Excel complains when we load it. I don't need to generate charts or anything like that, just export raw data.
I am thinking of flat CSV files, but Excel is a customer requirement. I can work with CSV directly, if I had a tool to convert to and from Excel. Given Excel 2007 is an xml-based (and zipped) file format, I am guessing this kind of library should be easy to find. However, what matters most to me are your comments and opinions.
EDIT: Ironically, in my opinion and following the answer with the most votes, the best Excel import&export library is no export at all. This is not the case for all scenarios, but it is for mine. XLS files support only 64k rows. XLSX supports up to 1M. The free libraries that I've tried feature bad performance (one second to load one row when you have 200k rows). I haven't tried the paid ones, as I feel they are overpriced for the value they deliver when all you need is a fast XLSX<->CSV conversion routine.