TimeZone.IsDaylightSavingTime Method

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Returns a value indicating whether a specified date and time is within a daylight saving time period.

Overloads

IsDaylightSavingTime(DateTime)	Returns a value indicating whether the specified date and time is within a daylight saving time period.
IsDaylightSavingTime(DateTime, DaylightTime)	Returns a value indicating whether the specified date and time is within the specified daylight saving time period.

IsDaylightSavingTime(DateTime)

Source:

TimeZone.cs

Returns a value indicating whether the specified date and time is within a daylight saving time period.

public:
 virtual bool IsDaylightSavingTime(DateTime time);

public virtual bool IsDaylightSavingTime (DateTime time);

abstract member IsDaylightSavingTime : DateTime -> bool
override this.IsDaylightSavingTime : DateTime -> bool

Public Overridable Function IsDaylightSavingTime (time As DateTime) As Boolean

Parameters

time

DateTime

A date and time.

Returns

Boolean

true if time is in a daylight saving time period; otherwise, false.

Remarks

The year to which the daylight saving time period applies is derived from the time parameter.

Because the TimeZone class supports a single daylight saving time adjustment rule, the IsDaylightSavingTime(DateTime) method applies the current adjustment rule to any date, regardless of whether the adjustment rule was in effect on that date. Assuming that the operating system itself has accurate historic daylight saving time data, a more accurate result is available by using the TimeZoneInfo.IsDaylightSavingTime method. Whenever possible, use the TimeZoneInfo.IsDaylightSavingTime method.

See also

• IsDaylightSavingTime(DateTime)

IsDaylightSavingTime(DateTime, DaylightTime)

Source:

TimeZone.cs

Returns a value indicating whether the specified date and time is within the specified daylight saving time period.

public:
 static bool IsDaylightSavingTime(DateTime time, System::Globalization::DaylightTime ^ daylightTimes);

public static bool IsDaylightSavingTime (DateTime time, System.Globalization.DaylightTime daylightTimes);

static member IsDaylightSavingTime : DateTime * System.Globalization.DaylightTime -> bool

Public Shared Function IsDaylightSavingTime (time As DateTime, daylightTimes As DaylightTime) As Boolean

Parameters

time

DateTime

A date and time.

daylightTimes

DaylightTime

A daylight saving time period.

Returns

Boolean

true if time is in daylightTimes; otherwise, false.

Exceptions

ArgumentNullException

daylightTimes is null.

Remarks

The TimeZoneInfo.IsDaylightSavingTime method provides the same functionality as this overload of the IsDaylightSavingTime method. Whenever possible, use the TimeZoneInfo.IsDaylightSavingTime method.

See also

• IsDaylightSavingTime(DateTime)