Call a method at a certain time

Question

I am developing an application that has a small feature of sending some SMS messages and Emails using some external web services.

These messages can be scheduled to be sent right now or in the future on a certain date at a certain time. They can also be scheduled to be sent every day/week/month.

How can I design my system to "know" when to call the sending method (without polling)?

Answer 1

You can use Quartz.net for task schedule. http://quartznet.sourceforge.net/

You can use this with windows service.

Answer 2

Or you have to use a kind of "External Scheduler" - which means - to use external polling, or to implement scheduler by yourself. I think that there's no any decisions without any polling at all...