I am looking for suggestions on how to handle a csv file that is being created, then uploaded by our customers, and that may have a comma in a value, like a company name.
Just use SoftCircuits.CsvParser on NuGet. It will handle all those details for you and efficiently handles very large files. And, if needed, it can even import/export objects by mapping columns to object properties. In addition, my testing showed it averages nearly 4 times faster than the popular CsvHelper.