TimeZoneInfo.IsInvalidTime Method

Indicates whether a particular date and time is invalid.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public bool IsInvalidTime(
	DateTime dateTime


Type: System.DateTime
A date and time value.

Return Value

Type: System.Boolean
true if dateTime is invalid; otherwise, false.

An invalid time falls within a range of times for the current time zone that cannot be mapped to Coordinated Universal Time (UTC) due to the application of an adjustment rule. Typically, invalid times occur when the time moves ahead for daylight saving time. See the Example section for an illustration.

The value of the Kind property of the dateTime parameter affects whether dateTime represents an invalid time, as the following table shows.

DateTime.Kind property

TimeZoneInfo object (if applicable)




Determines whether the time is invalid.


TimeZoneInfo.Utc or a non-local time zone.

Converts dateTime to the time of the TimeZoneInfo object and returns false.


Not applicable.

Assumes dateTime is the time of the TimeZoneInfo object and determines whether it is invalid.


Not applicable.

Returns false.

Version Notes

XNA Framework

 When this method is used in the XNA Framework, it throws a NotSupportedException exception.

In the Pacific Standard Time zone, which is the local time zone on the computer on which this example runs, daylight saving time begins at 2:00 A.M. on April 2, 2006. The following code passes the time at one-minute intervals from 1:59 A.M. on April 2, 2006, to 3:01 A.M. on April 2, 2006, to the IsInvalidTime method of a TimeZoneInfo object that represents the Pacific Standard Time zone. The console output indicates that all times from 2:00 A.M. on April 2, 2006, to 2:59 A.M. on April 2, 2006, are invalid.

// Specify DateTimeKind in Date constructor
DateTime baseTime = new DateTime(2007, 3, 11, 1, 59, 0, DateTimeKind.Unspecified);
DateTime newTime;

// List possible invalid times for a 63-minute interval, from 1:59 AM to 3:01 AM
// This assumes the local time zone is U.S. Pacific Standard Time.
for (int ctr = 0; ctr < 63; ctr++)
   // Because of assignment, newTime.Kind is also DateTimeKind.Unspecified
   newTime = baseTime.AddMinutes(ctr);
   outputBlock.Text += String.Format("{0} is invalid: {1}", newTime, 
                       TimeZoneInfo.Local.IsInvalidTime(newTime)) + "\n";


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

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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