獲取C＃中某個DateTime的星期一和星期日

Question

我有一個例如日期“ 2010-11-09，星期二 ”

現在我想得到星期一和星期日的日期時間，即上述日期。

你會怎么做？

Answer 1

這可能是你所追求的：

 DateTime date = DateTime.Today;

 // lastMonday is always the Monday before nextSunday.
 // When date is a Sunday, lastMonday will be tomorrow.     
 int offset = date.DayOfWeek - DayOfWeek.Monday;     
 DateTime lastMonday = date.AddDays(-offset);
 DateTime nextSunday = lastMonday.AddDays(6);

編輯：因為lastMonday並不總是顧名思義（見評論），所以下面的單行可能更重要：

 DateTime nextSunday = date.AddDays(7 - (int) date.DayOfWeek);

Answer 2

如果使用條件方法，這很容易

if (v_datetime.DayOfWeek== DayOfWeek.Sunday)
{
return true;
}

if (v_datetime.DayOfWeek== DayOfWeek.Monday)
{

}

Answer 3

/// <summary>
/// Returns the day that is the specific day of week of the input day.
/// </summary>
/// <param name="input">The input day.</param>
/// <param name="dayOfWeek">0 is Monday, 6 is Sunday.</param>
/// <returns></returns>
public static DateTime GetDayOfWeekOfSpecific(DateTime input, int dayOfWeek)
{
    if(input.DayOfWeek == DayOfWeek.Sunday)
    {
        dayOfWeek -= 7;
    }
    // lastMonday is always the Monday before nextSunday.
    // When today is a Sunday, lastMonday will be tomorrow.     
    int offset = input.DayOfWeek - DayOfWeek.Monday;
    DateTime lastMonday = input.AddDays(-offset);
    DateTime nextDayOfWeek = lastMonday.AddDays(dayOfWeek);
    return nextDayOfWeek;
}

Answer 4

像這樣的東西，當然你想在DateTime.MaxValue之前的某個點斷開循環，但這應該做：

  DateTime dt = DateTime.Parse("2010-11-09, Thuesday");


        while (dt < DateTime.MaxValue) 
        {

            if(dt.DayOfWeek == DayOfWeek.Sunday || dt.DayOfWeek == DayOfWeek.Monday)
                Console.WriteLine(dt.ToString());
            dt.AddDays(1);
        }

Answer 5

DateTime Monday = DateTime.Now.AddDays（（DateTime.Now.DayOfWeek - 1）* -1）。日期;

DateTime Sunday = DateTime.Now.AddDays（7 -DateTime.Now.DayOfWeek）.Date;