TimeZoneInfo.TransitionTime.IsFixedDateRule Proprietà
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Ottiene un valore che indica se la modifica dell'ora si verifica a una data e ora fisse, ad esempio il 1° novembre, o a una data e ora mobili, ad esempio l'ultima domenica del mese di ottobre.
public:
property bool IsFixedDateRule { bool get(); };public bool IsFixedDateRule { get; }member this.IsFixedDateRule : boolPublic ReadOnly Property IsFixedDateRule As BooleanValore della proprietà
true se la regola di modifica dell'ora è basata su una data fissa. false se la regola di modifica dell'ora è basata su una data mobile.
Esempio
Nell'esempio seguente vengono elencati gli orari di transizione da e verso l'ora legale per tutti i fusi orari disponibili nel sistema locale. Per i fusi orari con regole di data fissa, vengono visualizzate informazioni sull'ora di transizione dalle proprietà dell'oggetto TimeZoneInfo.TransitionTime . Per i fusi orari senza regole di data fissa, usa un Calendar oggetto che rappresenta il calendario di sistema corrente per determinare le date di inizio e fine effettive della transizione. Nell'esempio vengono visualizzati i risultati nella console.
private void GetTransitionTimes(int year)
{
// Instantiate DateTimeFormatInfo object for month names
DateTimeFormatInfo dateFormat = CultureInfo.CurrentCulture.DateTimeFormat;
// Get and iterate time zones on local computer
ReadOnlyCollection<TimeZoneInfo> timeZones = TimeZoneInfo.GetSystemTimeZones();
foreach (TimeZoneInfo timeZone in timeZones)
{
Console.WriteLine("{0}:", timeZone.StandardName);
TimeZoneInfo.AdjustmentRule[] adjustments = timeZone.GetAdjustmentRules();
int startYear = year;
int endYear = startYear;
if (adjustments.Length == 0)
{
Console.WriteLine(" No adjustment rules.");
}
else
{
TimeZoneInfo.AdjustmentRule adjustment = GetAdjustment(adjustments, year);
if (adjustment == null)
{
Console.WriteLine(" No adjustment rules available for this year.");
continue;
}
TimeZoneInfo.TransitionTime startTransition, endTransition;
// Determine if starting transition is fixed
startTransition = adjustment.DaylightTransitionStart;
// Determine if starting transition is fixed and display transition info for year
if (startTransition.IsFixedDateRule)
Console.WriteLine(" Begins on {0} {1} at {2:t}",
dateFormat.GetMonthName(startTransition.Month),
startTransition.Day,
startTransition.TimeOfDay);
else
DisplayTransitionInfo(startTransition, startYear, "Begins on");
// Determine if ending transition is fixed and display transition info for year
endTransition = adjustment.DaylightTransitionEnd;
// Does the transition back occur in an earlier month (i.e.,
// the following year) than the transition to DST? If so, make
// sure we have the right adjustment rule.
if (endTransition.Month < startTransition.Month)
{
endTransition = GetAdjustment(adjustments, year + 1).DaylightTransitionEnd;
endYear++;
}
if (endTransition.IsFixedDateRule)
Console.WriteLine(" Ends on {0} {1} at {2:t}",
dateFormat.GetMonthName(endTransition.Month),
endTransition.Day,
endTransition.TimeOfDay);
else
DisplayTransitionInfo(endTransition, endYear, "Ends on");
}
}
}
private static TimeZoneInfo.AdjustmentRule GetAdjustment(TimeZoneInfo.AdjustmentRule[] adjustments,
int year)
{
// Iterate adjustment rules for time zone
foreach (TimeZoneInfo.AdjustmentRule adjustment in adjustments)
{
// Determine if this adjustment rule covers year desired
if (adjustment.DateStart.Year <= year && adjustment.DateEnd.Year >= year)
return adjustment;
}
return null;
}
private void DisplayTransitionInfo(TimeZoneInfo.TransitionTime transition, int year, string label)
{
// For non-fixed date rules, get local calendar
Calendar cal = CultureInfo.CurrentCulture.Calendar;
// Get first day of week for transition
// For example, the 3rd week starts no earlier than the 15th of the month
int startOfWeek = transition.Week * 7 - 6;
// What day of the week does the month start on?
int firstDayOfWeek = (int) cal.GetDayOfWeek(new DateTime(year, transition.Month, 1));
// Determine how much start date has to be adjusted
int transitionDay;
int changeDayOfWeek = (int) transition.DayOfWeek;
if (firstDayOfWeek <= changeDayOfWeek)
transitionDay = startOfWeek + (changeDayOfWeek - firstDayOfWeek);
else
transitionDay = startOfWeek + (7 - firstDayOfWeek + changeDayOfWeek);
// Adjust for months with no fifth week
if (transitionDay > cal.GetDaysInMonth(year, transition.Month))
transitionDay -= 7;
Console.WriteLine(" {0} {1}, {2:d} at {3:t}",
label,
transition.DayOfWeek,
new DateTime(year, transition.Month, transitionDay),
transition.TimeOfDay);
}
open System
open System.Globalization
let displayTransitionInfo (transition: TimeZoneInfo.TransitionTime) year label =
// For non-fixed date rules, get local calendar
let cal = CultureInfo.CurrentCulture.Calendar
// Get first day of week for transition
// For example, the 3rd week starts no earlier than the 15th of the month
let startOfWeek = transition.Week * 7 - 6
// What day of the week does the month start on?
let firstDayOfWeek = cal.GetDayOfWeek(DateTime(year, transition.Month, 1)) |> int
// Determine how much start date has to be adjusted
let changeDayOfWeek = int transition.DayOfWeek
let transitionDay =
if firstDayOfWeek <= changeDayOfWeek then
startOfWeek + (changeDayOfWeek - firstDayOfWeek)
else
startOfWeek + (7 - firstDayOfWeek + changeDayOfWeek)
// Adjust for months with no fifth week
let transitionDay =
if transitionDay > cal.GetDaysInMonth(year, transition.Month) then
transitionDay - 7
else
transitionDay
printfn $" {label} {transition.DayOfWeek}, {DateTime(year, transition.Month, transitionDay):d} at {transition.TimeOfDay:t}"
let getAdjustment (adjustments: TimeZoneInfo.AdjustmentRule seq) year =
adjustments
// Iterate adjustment rules for time zone
// Determine if this adjustment rule covers year desired
|> Seq.tryFind (fun adjustment -> adjustment.DateStart.Year <= year && adjustment.DateEnd >= DateTime year)
|> Option.defaultValue null
let getTransitionTimes year =
// Instantiate DateTimeFormatInfo object for month names
let dateFormat = CultureInfo.CurrentCulture.DateTimeFormat
// Get and iterate time zones on local computer
let timeZones = TimeZoneInfo.GetSystemTimeZones()
for timeZone in timeZones do
printfn $"{timeZone.StandardName}:"
let adjustments = timeZone.GetAdjustmentRules()
let startYear = year
let mutable endYear = startYear
if adjustments.Length = 0 then
printfn " No adjustment rules."
else
let adjustment = getAdjustment adjustments year
if adjustment = null then
Console.WriteLine(" No adjustment rules available for this year.")
else
// Determine if starting transition is fixed
let startTransition = adjustment.DaylightTransitionStart
// Determine if starting transition is fixed and display transition info for year
if startTransition.IsFixedDateRule then
printfn $" Begins on {dateFormat.GetMonthName startTransition.Month} {startTransition.Day} at {startTransition.TimeOfDay:t}"
else
displayTransitionInfo startTransition startYear "Begins on"
// Determine if ending transition is fixed and display transition info for year
let mutable endTransition = adjustment.DaylightTransitionEnd
// Does the transition back occur in an earlier month (i.e.,
// the following year) than the transition to DST? If so, make
// sure we have the right adjustment rule.
if endTransition.Month < startTransition.Month then
endTransition <- (getAdjustment adjustments (year + 1)).DaylightTransitionEnd
endYear <- endYear + 1
if endTransition.IsFixedDateRule then
printfn $" Ends on {dateFormat.GetMonthName endTransition.Month} {endTransition.Day} at {endTransition.TimeOfDay:t}"
else
displayTransitionInfo endTransition endYear "Ends on"
Private Sub GetTransitionTimes(year As Integer)
' Get and iterate time zones on local computer
Dim timeZones As ReadOnlyCollection(Of TimeZoneInfo) = TimeZoneInfo.GetSystemTimeZones()
For Each timeZone As TimeZoneInfo In timeZones
Console.WriteLine("{0}:", timeZone.StandardName)
Dim adjustments() As TimeZoneInfo.AdjustmentRule = timeZone.GetAdjustmentRules()
Dim startYear As Integer = year
Dim endYear As Integer = startYear
If adjustments.Length = 0 Then
Console.WriteLine(" No adjustment rules.")
Else
Dim adjustment As TimeZoneInfo.AdjustmentRule = GetAdjustment(adjustments, year)
If adjustment Is Nothing Then
Console.WriteLine(" No adjustment rules available for this year.")
Continue For
End If
Dim startTransition, endTransition As TimeZoneInfo.TransitionTime
' Determine if starting transition is fixed
startTransition = adjustment.DaylightTransitionStart
' Determine if starting transition is fixed and display transition info for year
If startTransition.IsFixedDateRule Then
Console.WriteLine(" Begins on {0} {1} at {2:t}", _
MonthName(startTransition.Month), _
startTransition.Day, _
startTransition.TimeOfDay)
Else
DisplayTransitionInfo(startTransition, startYear, "Begins on")
End If
' Determine if ending transition is fixed and display transition info for year
endTransition = adjustment.DaylightTransitionEnd
' Does the transition back occur in an earlier month (i.e.,
' the following year) than the transition to DST? If so, make
' sure we have the right adjustment rule.
If endTransition.Month < startTransition.Month Then
endTransition = GetAdjustment(adjustments, year + 1).DaylightTransitionEnd
endYear += 1
End If
If endTransition.IsFixedDateRule Then
Console.WriteLine(" Ends on {0} {1} at {2:t}", _
MonthName(endTransition.Month), _
endTransition.Day, _
endTransition.TimeOfDay)
Else
DisplayTransitionInfo(endTransition, endYear, "Ends on")
End If
End If
Next
End Sub
Private Function GetAdjustment(adjustments As TimeZoneInfo.AdjustmentRule(), _
year As Integer) As TimeZoneInfo.AdjustmentRule
' Iterate adjustment rules for time zone
For Each adjustment As TimeZoneInfo.AdjustmentRule In adjustments
' Determine if this adjustment rule covers year desired
If adjustment.DateStart.Year <= year And adjustment.DateEnd.Year >= year Then
Return adjustment
End If
Next
Return Nothing
End Function
Private Sub DisplayTransitionInfo(transition As TimeZoneInfo.TransitionTime, year As Integer, label As String)
' For non-fixed date rules, get local calendar
Static cal As Calendar = CultureInfo.CurrentCulture.Calendar
' Get first day of week for transition
' For example, the 3rd week starts no earlier than the 15th of the month
Dim startOfWeek As Integer = transition.Week * 7 - 6
' What day of the week does the month start on?
Dim firstDayOfWeek As Integer = cal.GetDayOfWeek(New Date(year, transition.Month, 1))
' Determine how much start date has to be adjusted
Dim transitionDay As Integer
Dim changeDayOfWeek As Integer = transition.DayOfWeek
If firstDayOfWeek <= changeDayOfWeek Then
transitionDay = startOfWeek + (changeDayOfWeek - firstDayOfWeek)
Else
transitionDay = startOfWeek + (7 - firstDayOfWeek + changeDayOfWeek)
End If
' Adjust for months with no fifth week
If transitionDay > cal.GetDaysInMonth(year, transition.Month) Then
transitionDay -= 7
End If
Console.WriteLine(" {0} {1}, {2:d} at {3:t}", _
label, _
transition.DayOfWeek, _
New DateTime(year, transition.Month, transitionDay), _
transition.TimeOfDay)
End Sub
Commenti
Una regola di data fissa indica che la transizione avviene nella stessa data e ora di ogni anno a cui si applica la regola di rettifica. Ad esempio, una modifica dell'ora che si verifica ogni 3 novembre segue una regola di data fissa. Una regola di data mobile indica che la transizione avviene in un giorno specifico di una settimana specifica di un mese specifico per ogni anno a cui si applica la regola di rettifica. Ad esempio, una modifica dell'ora che si verifica la prima domenica di novembre segue una regola di data mobile.
Il valore della IsFixedDateRule proprietà determina le proprietà di un TimeZoneInfo.TransitionTime oggetto con valori validi. Nella tabella seguente vengono indicate le proprietà interessate dal valore della IsFixedDateRule proprietà .
| TransitionTime - proprietà | IsFixedDateRule = true | IsFixedDateRule = false |
|---|---|---|
Day |
Valido | Non utilizzato |
DayOfWeek |
Non utilizzato | Valido |
Week |
Non utilizzato | Valido |
Month |
Valido | Valido |
TimeOfDay |
Valido | Valido |