TimeZoneInfo.TransitionTime.IsFixedDateRule Vlastnost
Definice
Důležité
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Získá hodnotu určující, zda se časová změna vyskytuje v pevné datum a čas (například 1. listopadu) nebo plovoucí datum a čas (například poslední neděle v říjnu).
public:
property bool IsFixedDateRule { bool get(); };public bool IsFixedDateRule { get; }member this.IsFixedDateRule : boolPublic ReadOnly Property IsFixedDateRule As BooleanHodnota vlastnosti
true pokud je pravidlo změny času pevné datum; false pokud je pravidlo změny času plovoucí na datum.
Příklady
Následující příklad uvádí čas přechodu na letní čas a z letního času pro všechny časové zóny, které jsou k dispozici v místním systému. U časových pásem s pravidly s pevným datem zobrazuje informace o čase přechodu z vlastností objektu TimeZoneInfo.TransitionTime . U časových pásem bez pravidel s pevným datem používá Calendar objekt, který představuje aktuální systémový kalendář k určení skutečných počátečních a koncových dat přechodu. V příkladu se zobrazí výsledky konzoly.
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
Poznámky
Pravidlo s pevným datem označuje, že přechod probíhá ve stejném datu a čase každého roku, na který se pravidlo úpravy vztahuje. Například časová změna, která nastane každou 3. listopadu, se řídí pravidlem s pevným datem. Pravidlo s plovoucí desetinou čárkou označuje, že přechod probíhá v určitém dni v určitém týdnu konkrétního měsíce pro každý rok, na který se pravidlo úpravy vztahuje. Například časová změna, která nastane v první neděli v listopadu, se řídí pravidlem s plovoucí desetinou čárkou.
Hodnota IsFixedDateRule vlastnosti určuje, které vlastnosti objektu TimeZoneInfo.TransitionTime mají platné hodnoty. Následující tabulka označuje, které vlastnosti jsou ovlivněny hodnotou IsFixedDateRule vlastnosti.
| Vlastnost TransitionTime | IsFixedDateRule = true | IsFixedDateRule = false |
|---|---|---|
Day |
Platné | Nepoužitý |
DayOfWeek |
Nepoužitý | Platné |
Week |
Nepoužitý | Platné |
Month |
Platné | Platné |
TimeOfDay |
Platné | Platné |