Typically, a number of time zones defined in the registry have the same offset from Coordinated Universal Time (UTC) and the same adjustment rules. The following example displays a list of these time zones to the console.
Dim timeZones As ReadOnlyCollection(Of TimeZoneInfo) = TimeZoneInfo.GetSystemTimeZones()
Dim timeZoneArray(timeZones.Count - 1) As TimeZoneInfo
timeZones.CopyTo(timeZoneArray, 0)
'Dim arrayPtr As Integer = 1
' Iterate array from top to bottom
For ctr As Integer = timeZoneArray.GetUpperBound(0) To 1 Step -1
' Get next item from top
Dim thisTimeZone As TimeZoneInfo = timeZoneArray(ctr)
For compareCtr As Integer = 0 To ctr - 1
' Determine if time zones have the same rules
If thisTimeZone.HasSameRules(timeZoneArray(compareCtr)) Then
Console.WriteLine("{0} has the same rules as {1}", _
thisTimeZone.StandardName, _
timeZoneArray(compareCtr).StandardName)
End If
Next
Next
ReadOnlyCollection<TimeZoneInfo> timeZones = TimeZoneInfo.GetSystemTimeZones();
TimeZoneInfo[] timeZoneArray = new TimeZoneInfo[timeZones.Count];
timeZones.CopyTo(timeZoneArray, 0);
// Iterate array from top to bottom
for (int ctr = timeZoneArray.GetUpperBound(0); ctr >= 1; ctr--)
{
// Get next item from top
TimeZoneInfo thisTimeZone = timeZoneArray[ctr];
for (int compareCtr = 0; compareCtr <= ctr - 1; compareCtr++)
{
// Determine if time zones have the same rules
if (thisTimeZone.HasSameRules(timeZoneArray[compareCtr]))
{
Console.WriteLine("{0} has the same rules as {1}",
thisTimeZone.StandardName,
timeZoneArray[compareCtr].StandardName);
}
}
}