DateTimeOffset.AddDays(Double) 方法

定義

命名空間:

System

組件:

netstandard.dll, System.Runtime.dll

來源:

DateTimeOffset.cs

回傳一個新 DateTimeOffset 物件，為該實例的值加上指定數量的整天與分數日。

public:
 DateTimeOffset AddDays(double days);

public DateTimeOffset AddDays(double days);

member this.AddDays : double -> DateTimeOffset

Public Function AddDays (days As Double) As DateTimeOffset

參數

days

Double

整天和分段日數。 這個數字可以是負數或正數。

傳回

DateTimeOffset

一個物件，其值為當前 DateTimeOffset 物件所代表的日期與時間與所 days代表的天數之和。

例外狀況

ArgumentOutOfRangeException

所得值 DateTimeOffset 小於 DateTimeOffset.MinValue。

-或-

所得值 DateTimeOffset 大於 DateTimeOffset.MaxValue。

範例

以下範例使用該 AddDays 方法列出2008年3月工作週開始的星期一日期。

DateTimeOffset workDay = new DateTimeOffset(2008, 3, 1, 9, 0, 0,
                   DateTimeOffset.Now.Offset);
int month = workDay.Month;
// Start with the first Monday of the month
if (workDay.DayOfWeek != DayOfWeek.Monday)
{
   if (workDay.DayOfWeek == DayOfWeek.Sunday)
      workDay = workDay.AddDays(1);
   else
      workDay = workDay.AddDays(8 - (int)workDay.DayOfWeek);
}
Console.WriteLine("Beginning of Work Week In {0:MMMM} {0:yyyy}:", workDay);
// Add one week to the current date
do
{
   Console.WriteLine("   {0:dddd}, {0:MMMM}{0: d}", workDay);
   workDay = workDay.AddDays(7);
} while (workDay.Month == month);
// The example produces the following output:
//    Beginning of Work Week In March 2008:
//       Monday, March 3
//       Monday, March 10
//       Monday, March 17
//       Monday, March 24
//       Monday, March 31

let workDay = DateTimeOffset(2008, 3, 1, 9, 0, 0, DateTimeOffset.Now.Offset)
let month = workDay.Month

// Start with the first Monday of the month
let mutable workDay = 
    match workDay.DayOfWeek with
    | DayOfWeek.Monday ->
        workDay
    | DayOfWeek.Sunday ->
        workDay.AddDays 1
    | _ ->
        workDay.AddDays(8. - float workDay.DayOfWeek)

printfn $"Beginning of Work Week In {workDay:MMMM} {workDay:yyyy}:"

// Add one week to the current date
while workDay.Month = month do
    printfn $"   {workDay:dddd}, {workDay:MMMM}{workDay: d}"
    workDay <- workDay.AddDays 7

// The example produces the following output:
//    Beginning of Work Week In March 2008:
//       Monday, March 3
//       Monday, March 10
//       Monday, March 17
//       Monday, March 24
//       Monday, March 31

Dim workDay As New DateTimeOffset(#3/1/2008 9:00AM#, _
                   DateTimeOffset.Now.Offset)
Dim month As Integer = workDay.Month
' Start with the first Monday of the month
If workDay.DayOfWeek <> DayOfWeek.Monday Then
   If workDay.DayOfWeek = DayOfWeek.Sunday Then
      workDay = workDay.AddDays(1)
   Else   
      workDay = workDay.AddDays(8 - CInt(workDay.DayOfWeek))
   End If
End If
Console.WriteLine("Beginning of Work Week In {0:MMMM} {0:yyyy}:", workDay)
' Add one week to the current date 
Do While workDay.Month = month
   Console.WriteLine("   {0:dddd}, {0:MMMM}{0: d}", workDay)
   workDay = workDay.AddDays(7)
Loop        
' The example produces the following output:
'    Beginning of Work Week In March 2008:
'       Monday, March 3
'       Monday, March 10
'       Monday, March 17
'       Monday, March 24
'       Monday, March 31

備註

參數的 days 分數部分是一天的分數部分。 例如，4.5 相當於 4 天 12 小時 0 分鐘 0 秒 0 毫秒。

在 .NET Framework 中，參數 days 會四捨五入到最接近的毫秒。 在 .NET 7 及之後版本中，參數的精確度會被使用。Doubledays 然而，由於浮點數學本身的不精確性，所得精度會有所不同。

備註

此方法回傳一個新 DateTimeOffset 物件。 它不會透過增加 days 日期和時間來改變當前物件的值。

由於物件 DateTimeOffset 不代表特定時區的日期與時間， AddDays 該方法在執行日期與時間運算時，不會考慮該時區的調整規則。

將少於一天的時間間隔轉換為分數可能會損失精確度。 如果這有問題，你可以使用這個 Add 方法，它讓你能在單一方法呼叫中指定多種時間區間，省去將時間區間轉換成一天中的分數。