In general, Time zone manipulation can't be done directly in classic ASP.
However, if you have full control of the server where the code is running, you can install a COM component written in a language that does have time zone support, then use that component from your classic ASP environment.
For example, you might write the following component in .NET with C#:
using System;
using System.Runtime.InteropServices;
namespace TimeZoneInfoCom
{
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.AutoDispatch)]
[Guid("E0C70A94-352D-4C0B-8C2E-8066C88565C5")]
public class TimeZoneConverter
{
public DateTime NowInZone(string timeZoneId)
{
return TimeZoneInfo.ConvertTimeBySystemTimeZoneId(DateTime.UtcNow, timeZoneId);
}
public DateTime Convert(DateTime dateTime, string sourceZoneId, string targetZoneId)
{
TimeZoneInfo sourceTimeZone = TimeZoneInfo.FindSystemTimeZoneById(sourceZoneId);
TimeZoneInfo targetTimeZone = TimeZoneInfo.FindSystemTimeZoneById(targetZoneId);
return TimeZoneInfo.ConvertTime(dateTime, sourceTimeZone, targetTimeZone);
}
}
}
You would then compile this, copy the DLL to your server, and register it as a COM component (using RegAsm.exe).
Then you could call it in your Classic ASP page, like so:
<html>
<body>
Server Time: <%= Now() %><br>
<br>
<%
Dim tzconverter
Set tzconverter = Server.CreateObject("TimeZoneInfoCom.TimeZoneConverter")
%>
US Pacific Time: <%= tzconverter.NowInZone("Pacific Standard Time") %><br>
US Mountain Time: <%= tzconverter.NowInZone("Mountain Standard Time") %><br>
US Central Time: <%= tzconverter.NowInZone("Central Standard Time") %><br>
US Eastern Time: <%= tzconverter.NowInZone("Eastern Standard Time") %><br>
UTC: <%= tzconverter.NowInZone("UTC") %><br>
<br>
Conversion Example:
<%
Dim originalTime, convertedTime
originalTime = #12/31/2014 00:00:00#
convertedTime = tzconverter.Convert(originalTime, "UTC", "Tokyo Standard Time")
Response.Write(convertedTime)
%>
<%
' Don't forget to destroy the com object!
Set tzconverter = Nothing
%>
</body>
</html>
If you get an "ActiveX component can't create object" error, be sure that you have set "Enable 32-Bit Applications" to True in IIS, under the advanced settings for your application pool.
With regard to SQL Server - If you search, you may find a handful of posts showing ways you can manipulate time in SQL Server, through elaborate stored procedures that either have fixed offsets, fixed time zone rules, or rely on tables of time zone data. I usually advise against any of these approaches because they are too brittle.
- Fixed offsets are bad because they don't account for daylight saving time.
- Fixed rules are bad because time zone rules can (and do) change. Editing stored procs to keep up with these changes is too fragile (IMHO).
- Maintaining tables of time zone data is a little better, but usually I find these tables to not be maintained well. If you go down this route, be sure to put a procedure in place for updating the tables periodically.
