Is there an enum for the ContentType property on a HttpWebResponse ("text/plain", "application/octet-stream" etc.)?

The closest thing I could find was System.Net.Mime.MediaTypeNames but that doesn't seem to have everything (like json) since it seems to be more focused around email attachments.

Solution 1:

An enum doesn't make much sense. MIME types are open-ended. That is, the list is not finite: new types are added from time to time.

See RFC4288: Media Type Specifications and Registration Procedures

Solution 2:

IANA's database is most likely to be complete. Currently, they have the list available in CSV format at https://www.iana.org/assignments/media-types/application.csv. I am assuming this is a stable URL whose content changes as updates are made. If you want to stay up to date, you'd need to put together a mechanism that is appropriate for your needs.

There is also the mime.types file that comes with Apache which seems to have been derived from the said list.