Cookie.Expires from ASP.NET Request Object Always DateTime.MinValue
I’ve been working on a problem today involving cookies with one of our web applications. The cookie is keeping track of a user’s authenticated session and it’s timing people out too soon. So, I was checking the expiration time of the cookie coming in from the browser and it was returning 1/1/0001 12:00AM every time. I thought this might be the source of my problem, but resetting the cookie and the expiration time did not help the next round-trip to the server. The cookie still read the DateTime.MinValue time.
The articles explains why this happens. The summary: the browser maintains the cookie and handles its expiration. Therefore, it does not send this information back to the server when making a request. So, you can never read the expiration time of a cookie on the server from the Request object.