So the company I'm working for is looking for a means to verify that a given .xls/.xlsx file is valid. Which means checking columns and rows and other data. He's having me evaluate GrapeCity Spread and SpreadsheetGear, but I'm wondering if anyone else has any other suggestions of external tools to check out. We don't need a means to export .xls files or anything like that, just the ability to import them and verify they are valid based on a set of criteria I create. Thanks.