How to send reminder emails based on users input time and day (based on their time zone)

I need to send emails based on users input time and day (based on their time zone)? Kind of a reminder.

For Example: User input 2:00pm Eastern Time on my server I have different time zone, how to calculate the time and send the email at users time-zone.

Its a web application. What is the best way to accomplish it using asp.net c#? If somebody already done it in the past I will be glad to tak开发者_如何学运维e a look at source code. Thank you for useful suggestions.

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Anytime timezone matters, store and manipulate the dates as UTC. If the user asks to have an email sent at 2PM EST, send it at 18:00 UTC (EST is -5 UTC).

You will need to determine their timezone by either asking for it or, perhaps, by figuring it out using something like http://ipinfodb.com (based on IP address).

In .Net you can convert the time using the TimeZoneInfo object.

var local = new DateTime(DateTime.Now.Ticks, DateTimeKind.Unspecified);
var tzi = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
var utc = TimeZoneInfo.ConvertTimeToUtc(local, tzi);