TimeZoneInfo.GetAmbiguousTimeOffsets Method (DateTime)
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Returns information about the possible dates and times that an ambiguous date and time can be mapped to.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Function GetAmbiguousTimeOffsets ( _
dateTime As DateTime _
) As TimeSpan()
public TimeSpan[] GetAmbiguousTimeOffsets(
DateTime dateTime
)
Parameters
- dateTime
Type: System.DateTime
A date and time.
Return Value
Type: array<System.TimeSpan[]
An array of TimeSpan objects that represents possible Coordinated Universal Time (UTC) offsets that a particular date and time can be mapped to.
Remarks
The precise behavior of this method depends on the relationship between the Kind property and the TimeZoneInfo object, as the following table shows.
TimeZoneInfo object type |
Kind property value |
Behavior |
|---|---|---|
Returns ambiguous time offsets for dateTime. |
||
Converts dateTime to the local time, and then returns ambiguous time offsets for that time. |
||
Any value. |
Throws an ArgumentException. |
|
Any other time zone. |
Converts dateTime to the specified time zone, and then determines whether that time is ambiguous. |
|
Any other time zone. |
Determines whether dateTime is ambiguous in the specified time zone. |
The order of TimeSpan objects in the array returned by this method is undefined. However, you can determine which element represents an offset from the time zone's standard time by comparing its value with the time zone's BaseUtcOffset property.
Version Notes
XNA Framework
When this method is used in the XNA Framework, it throws a NotSupportedException exception.
Examples
The following example defines a method named ShowPossibleUtcTimes that uses the GetAmbiguousTimeOffsets(DateTime) method to map an ambiguous time to its possible corresponding Coordinated Universal Time (UTC) times.
Private Sub ShowPossibleUtcTimes(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal ambiguousTime As Date, ByVal timeZone As TimeZoneInfo)
' Determine if time is ambiguous in target time zone
If Not timeZone.IsAmbiguousTime(ambiguousTime) Then
outputBlock.Text &= String.Format("{0} is not ambiguous in time zone {1}.", _
ambiguousTime, _
timeZone.DisplayName) & vbCrLf
Else
' Display time and its time zone (local, UTC, or indicated by timeZone argument)
Dim originalTimeZoneName As String
If ambiguousTime.Kind = DateTimeKind.Utc Then
originalTimeZoneName = "UTC"
ElseIf ambiguousTime.Kind = DateTimeKind.Local Then
originalTimeZoneName = "local time"
Else
originalTimeZoneName = timeZone.DisplayName
End If
outputBlock.Text &= String.Format("{0} {1} maps to the following possible times:", _
ambiguousTime, originalTimeZoneName) & vbCrLf
' Get ambiguous offsets
Dim offsets() As TimeSpan = timeZone.GetAmbiguousTimeOffsets(ambiguousTime)
' Display each offset and its mapping to UTC
For Each offset As TimeSpan In offsets
If offset.Equals(timeZone.BaseUtcOffset) Then
outputBlock.Text &= String.Format("If {0} is {1}, {2} UTC", ambiguousTime, timeZone.StandardName, ambiguousTime - offset) & vbCrLf
Else
outputBlock.Text &= String.Format("If {0} is {1}, {2} UTC", ambiguousTime, timeZone.DaylightName, ambiguousTime - offset) & vbCrLf
End If
Next
End If
End Sub
private void ShowPossibleUtcTimes(System.Windows.Controls.TextBlock outputBlock,
DateTime ambiguousTime, TimeZoneInfo timeZone)
{
// Determine if time is ambiguous in target time zone
if (!timeZone.IsAmbiguousTime(ambiguousTime))
{
outputBlock.Text += String.Format("{0} is not ambiguous in time zone {1}.",
ambiguousTime,
timeZone.DisplayName) + "\n";
}
else
{
// Display time and its time zone (local, UTC, or indicated by timeZone argument)
string originalTimeZoneName;
if (ambiguousTime.Kind == DateTimeKind.Utc)
originalTimeZoneName = "UTC";
else if (ambiguousTime.Kind == DateTimeKind.Local)
originalTimeZoneName = "local time";
else
originalTimeZoneName = timeZone.DisplayName;
outputBlock.Text += String.Format("{0} {1} maps to the following possible times:",
ambiguousTime, originalTimeZoneName) + "\n";
// Get ambiguous offsets
TimeSpan[] offsets = timeZone.GetAmbiguousTimeOffsets(ambiguousTime);
// Display each offset and its mapping to UTC
foreach (TimeSpan offset in offsets)
{
if (offset.Equals(timeZone.BaseUtcOffset))
outputBlock.Text += String.Format("If {0} is {1}, {2} UTC", ambiguousTime, timeZone.StandardName, ambiguousTime - offset) + "\n";
else
outputBlock.Text += String.Format("If {0} is {1}, {2} UTC", ambiguousTime, timeZone.DaylightName, ambiguousTime - offset) + "\n";
}
}
}
The method can then be called using code such as the following:
ShowPossibleUtcTimes(outputBlock, #11/4/2007 1:00:00 AM#, _
TimeZoneInfo.Local)
'
' This example produces the following output if run in the Pacific time zone:
'
' 11/4/2007 1:00:00 AM (GMT-08:00) Pacific Time (US & Canada) maps to the following possible times:
' If 11/4/2007 1:00:00 AM is Pacific Standard Time, 11/4/2007 9:00:00 AM UTC
' If 11/4/2007 1:00:00 AM is Pacific Daylight Time, 11/4/2007 8:00:00 AM UTC
'
ShowPossibleUtcTimes(outputBlock, new DateTime(2007, 11, 4, 1, 0, 0),
TimeZoneInfo.Local);
//
// This example produces the following output if run in the Pacific time zone:
//
// 11/4/2007 1:00:00 AM (GMT-08:00) Pacific Time (US & Canada) maps to the following possible times:
// If 11/4/2007 1:00:00 AM is Pacific Standard Time, 11/4/2007 9:00:00 AM UTC
// If 11/4/2007 1:00:00 AM is Pacific Daylight Time, 11/4/2007 8:00:00 AM UTC
//
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
See Also