/// <summary>
/// Enumerate the available time zones
/// </summary>
/// <returns>The list of known time zones</returns>
public static TimeZoneInformation[] EnumZones()
{
if (s_zones == null)
{
lock ( s_lockZones )
{
if (s_zones == null)
{
List <TimeZoneInformation> zones = new List <TimeZoneInformation>();
using (RegistryKey key =
Registry.LocalMachine.OpenSubKey(
@"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones"))
{
string[] zoneNames = key.GetSubKeyNames();
foreach (string zoneName in zoneNames)
{
using (RegistryKey subKey = key.OpenSubKey(zoneName))
{
TimeZoneInformation tzi = new TimeZoneInformation();
tzi.m_name = zoneName;
tzi.m_displayName = (string)subKey.GetValue("Display");
tzi.m_standardName = (string)subKey.GetValue("Std");
tzi.m_daylightName = (string)subKey.GetValue("Dlt");
tzi.InitTzi((byte[])subKey.GetValue("Tzi"));
tzi.m_index = (int)(subKey.GetValue("Index", zones.Count + 1));
zones.Add(tzi);
}
}
}
zones.Sort(CompareByTzOffset);
s_zones = zones.ToArray();
}
}
}
return(s_zones);
}
/// <summary>
/// Enumerate the available time zones
/// </summary>
/// <returns>The list of known time zones</returns>
public static TimeZoneInformation[] EnumZones()
{
if ( s_zones == null )
{
lock( s_lockZones )
{
if ( s_zones == null )
{
List<TimeZoneInformation> zones = new List<TimeZoneInformation>();
using ( RegistryKey key =
Registry.LocalMachine.OpenSubKey(
@"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones" ) )
{
string[] zoneNames = key.GetSubKeyNames();
foreach ( string zoneName in zoneNames )
{
using ( RegistryKey subKey = key.OpenSubKey( zoneName ) )
{
TimeZoneInformation tzi = new TimeZoneInformation();
tzi.m_name = zoneName;
tzi.m_displayName = (string) subKey.GetValue( "Display" );
tzi.m_standardName = (string) subKey.GetValue( "Std" );
tzi.m_daylightName = (string) subKey.GetValue( "Dlt" );
tzi.InitTzi( (byte[]) subKey.GetValue( "Tzi" ) );
tzi.m_index = (int)(subKey.GetValue("Index", zones.Count + 1));
zones.Add( tzi );
}
}
}
zones.Sort(CompareByTzOffset);
s_zones = zones.ToArray();
}
}
}
return s_zones;
}
public static int CompareByTzOffset(TimeZoneInformation left, TimeZoneInformation right)
{
return right.Bias - left.Bias;
}
/// <summary>
/// Convert a time from the time zone with the supplied index to UTC.
/// </summary>
/// <param name="index">The time zone index.</param>
/// <param name="utc">The time to convert.</param>
/// <returns>The converted time.</returns>
/// <exception cref="ArgumentOutOfRangeException">Thrown if the index is not found.</exception>
/// <exception cref="NotSupportedException">Thrown if the method failed due to missing platform support.</exception>
public static DateTime ToUniversalTime(int index, DateTime local)
{
TimeZoneInformation tzi = FromIndex(index);
return(tzi.ToUniversalTime(local));
}
/// <summary>
/// Convert a time from UTC to the time zone with the supplied index.
/// </summary>
/// <param name="index">The time zone index.</param>
/// <param name="utc">The time to convert.</param>
/// <returns>The converted time.</returns>
/// <exception cref="ArgumentOutOfRangeException">Thrown if the index is not found.</exception>
public static DateTime FromUniversalTime(int index, DateTime utc)
{
TimeZoneInformation tzi = FromIndex(index);
return(tzi.FromUniversalTime(utc));
}
public static int CompareByTzOffset(TimeZoneInformation left, TimeZoneInformation right)
{
return(right.Bias - left.Bias);
}