使用VB.NET查找一周内星期一的日期-Java 学习之路

我需要找到一种方法来查找我们所在的任何一周的星期一的日期（DD / MM / YYYY） .

例如，本周，星期一将是09/11/2009，如果这是下周，那将是2009年11月16日 .

我设法以代码的形式获得了某个地方，但我得到的只是“无法转换为整数”错误 . 我正在使用Date.Today和AddDays（） .

谢谢你的帮助 . :)

9 回答

如果星期日是一周的第一天，你可以简单地这样做：

Dim today As Date = Date.Today
Dim dayDiff As Integer = today.DayOfWeek - DayOfWeek.Monday
Dim monday As Date = today.AddDays(-dayDiff)

如果星期一是一周的第一天：

Dim today As Date = Date.Today
Dim dayIndex As Integer = today.DayOfWeek
If dayIndex < DayOfWeek.Monday Then
    dayIndex += 7 'Monday is first day of week, no day of week should have a smaller index
End If
Dim dayDiff As Integer = dayIndex - DayOfWeek.Monday
Dim monday As Date = today.AddDays(-dayDiff)

回复于 2024-05-04T13:50:07+08:00

我刚刚在一个正在研究的项目中做到这一点 - 我保证，这是正确的 . 这是一个在给定日期之后返回第n个星期一的方法 . 如果给定日期是星期一，则返回下一个星期一 .

Public Function GetSubsequentMonday(ByVal startDate As DateTime, ByVal subsequentWeeks As Integer) As DateTime
    Dim dayOfWeek As Integer = CInt(startDate.DayOfWeek)
    Dim daysUntilMonday As Integer = (Math.Sign(dayOfWeek) * (7 - dayOfWeek)) + 1
    'number of days until the next Monday
    Return startDate.AddDays(CDbl((daysUntilMonday + (7 * (subsequentWeeks - 1)))))
End Function

回复于 2024-05-04T13:50:07+08:00

如果星期一是第一天，另一种方法是：

Dim today As Date = Date.Today
                Dim dayDiff As Integer = today.DayOfWeek - DayOfWeek.Monday
                Dim monday As Date = today.AddDays(-dayDiff)

                dayDiff = DayOfWeek.Saturday - today.DayOfWeek + 1
                Dim sunday As Date = today.AddDays(dayDiff)

回复于 2024-05-04T13:50:07+08:00

一个简单的方法应该得到你想要的：

private static DateTime GetMondayForWeek(DateTime inputDate)
    {
        int daysFromMonday = inputDate.DayOfWeek - DayOfWeek.Monday;
        return inputDate.AddDays(-daysFromMonday);
    }

您也可以将它扩展到您想要的任何一天：

private static DateTime GetDayForWeek(DateTime inputDate, DayOfWeek inputDay)
    {
        int daysAway = inputDate.DayOfWeek - inputDay;
        return inputDate.AddDays(-daysAway);
    }

要调用第一个示例，只需使用以下内容：

DateTime mondayDate = GetMondayForWeek(new DateTime(2009, 11, 15));
Console.WriteLine(mondayDate);

回复于 2024-05-04T13:50:07+08:00

36
DateTime.DayOfWeek是一个枚举，指示给定日期的哪一天 . 由于星期一是1，您可以使用以下代码找到当周的星期一：
```
Dim monday As DateTime = Today.AddDays((Today.DayOfWeek - DayOfWeek.Monday) * -1)
```
回复于 2024-05-04T13:50:07+08:00

如果您的周从星期一开始，那么您可以使用以下内容：

DateTime mondayDate = DateTime.Now.AddDays(((DateTime.Now.DayOfWeek == DayOfWeek.Sunday?7: (int)DateTime.Now.DayOfWeek) - 1)*-1);

DateTime sundayDate = DateTime.Now.AddDays(7 - (DateTime.Now.DayOfWeek == DayOfWeek.Sunday?7: (int)DateTime.Now.DayOfWeek ));

回复于 2024-05-04T13:50:07+08:00

1
您可以使用星期几方法
```
Dim instance As DateTime
Dim value As DayOfWeek

value = instance.DayOfWeek
```
见：http://msdn.microsoft.com/en-us/library/system.datetime.dayofweek.aspx
回复于 2024-05-04T13:50:07+08:00

=Format(DateAdd("d", (-1 * WeekDay(Date.Today()) + 2), Date.Today()), "dd/MM/yyyy")

回复于 2024-05-04T13:50:07+08:00

继我对Meta-Knight的回答之后，这是一个简短的函数，我在评论中提到了更正：

Public Function GetFirstOfLastWeek() As DateTime
Dim today As DateTime, daysSinceMonday As Integer
    today = DateTime.Today
    daysSinceMonday = today.DayOfWeek - DayOfWeek.Monday
    If daysSinceMonday < 0 Then
        daysSinceMonday += 7
    End If
    Return today.AddDays(-daysSinceMonday)  
End Function

回复于 2024-05-04T13:50:07+08:00

使用VB.NET查找一周内星期一的日期

9 回答

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