查找上一个完成周的周结束日期

对于任何给定日期，如果您的周从周日到周六，您将如何找到上一个完整周的周结束日期？

Answer 1

 DateTime StartOfWeek = DateTime.Today.AddDays(-(int)DateTime.Today.DayOfWeek); DateTime EndOfLastWeek = StartOfWeek.AddDays(-1); 

Answer 2

 DateTime givenDate; // = ... int daysToOffset = ((int)givenDate.DayOfWeek + 1) * -1; DateTime lastDayOfLastCompletedWeek = givenDate.AddDays(daysToOffset); 

Answer 3

.NET DateTimes公开DayOfWeek属性。 在这种情况下，您可以利用它：

 var currDay = DateTime.Today.DayOfWeek; //currday is now an enumeration with Sunday=0, Saturday=6 //We can cast that to a number and subtract to get to the previous Saturday var EndOfLastWeek = DateTime.Today.AddDays(((int)currDay+1)*-1); 

Answer 4

  public static DateTime EndOfWeek(DateTime dateTime) { DateTime start = StartOfWeek(dateTime); return start.AddDays(6); } public static DateTime StartOfWeek(DateTime dateTime) { int days = dateTime.DayOfWeek - DayOfWeek.Monday; if (days < 0) days += 7; return dateTime.AddDays(-1 * days).Date; } 

要查找上周结束，只需致电：

  DateTime endPrevWeek = StartOfWeek(DateTime.Today).AddDays(-1); 

Answer 5

如果要指定哪一天是星期结束，并且您不想担心系统定义为星期的默认开始日期，请使用以下方法：

 private static DateTime GetPreviousSpecifiedDayOfWeek(DateTime dt, DayOfWeek day) { if (dt.DayOfWeek == day) { return dt; } while (dt.DayOfWeek != day) { dt = dt.AddDays(-1); } return dt; }