Question

我有以下代码列出两个日期之间每个月的最后一天但我的问题是我没有从这几个月的最后一天获得。

例如：Date1: 31/10/2017 Date2: 31/3/2018

我的结果：

应该是

代码：

Dim startDay As Date = StartDate.SelectedDate
Dim endDay As Date = EndDate.SelectedDate
Dim dayCtr As Date
dayCtr = startDay
Do While (dayCtr <= endDay)
     ' MsgBox(dayCtr.Date.Day & "-" & dayCtr.Date.DayOfWeek.ToString())
      ListBox1.Items.Add(dayCtr.Date.Day & "-" & dayCtr.Date.Month.ToString() & "-" & dayCtr.Date.Year.ToString())
      dayCtr = dayCtr.AddMonths(1)
Loop

感谢

Answer 1

AddMonth（1）在日期的月份组件中加1（并且好好包裹到下一年，所以你不必这样做）但其余的由你决定。

Private Function GetLastDayOfMonth(currentDate As Date) As Date
    Dim result As Date
    'Jump one Month ahead 
    result = currentDate.AddMonths(1)
    'Go to first day of that Month
    result = New Date(result.Year, result.Month, 1)
    'Go one day back
    result = result.AddDays(-1)
    Return result

End Function

在您的代码中使用此功能，如下所示：

Dim startDay As Date = StartDate.SelectedDate
Dim endDay As Date = EndDate.SelectedDate
Dim dayCtr As Date
dayCtr = startDay
Do While (dayCtr <= endDay)

    ' MsgBox(dayCtr.Date.Day & "-" & dayCtr.Date.DayOfWeek.ToString())
    Dim lastDay As Date = GetLastDayOfMonth(dayCtr)
    ListBox1.Items.Add(lastDay.Date.Day & "-" & lastDay.Date.Month.ToString() & "-" & lastDay.Date.Year.ToString())
    dayCtr = dayCtr.AddMonths(1)
Loop

你应该没事。 .NET可以帮助您处理日期，但仍需要一点肘部油脂。

Answer 2

在没有额外操作的情况下使用Date.DaysInMonth方法的投标方法很少

Private Iterator Function GetLastDatesFrom(startDate As Date, 
                                           endDate As Date) As IEnumerable(Of Date)
    Dim temp = startDate
    Do While (temp <= endDate)
        Dim lastDay = Date.DaysInMonth(temp.Year, temp.Month)
        Yield New Date(temp.Year, temp.Month, lastDay)

        temp = temp.AddMonths(1)
    Loop
End Function

然后

Dim startDay As Date = StartDate.SelectedDate
Dim endDay As Date = EndDate.SelectedDate

Dim dates = GetLastDatesFromRange(startDay, endDay).ToList()
ListBox1.Items.AddRange(dates)

列出asp.net两个日期之间的月份

2 个答案: