できるかを取得しましたDateTimeのが始ます。

Question

わからの開始曜（日曜日と月曜日かりで、現在の時にクライアントまで、フルのC#?

のようなもの:

DateTime.Now.StartWeek(Monday);

Answer 1

延長方法。彼らは答えもん!;)

public static class DateTimeExtensions
{
    public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
    {
        int diff = (7 + (dt.DayOfWeek - startOfWeek)) % 7;
        return dt.AddDays(-1 * diff).Date;
    }
}

できるこんなところに使用されています:

DateTime dt = DateTime.Now.StartOfWeek(DayOfWeek.Monday);
DateTime dt = DateTime.Now.StartOfWeek(DayOfWeek.Sunday);

Answer 2

素早い方までには:

var sunday = DateTime.Today.AddDays(-(int)DateTime.Today.DayOfWeek);

ただその他の曜日を開始日までの追加のDayOfWeek価値の

var monday = DateTime.Today.AddDays(-(int)DateTime.Today.DayOfWeek + (int)DayOfWeek.Monday);

var tuesday = DateTime.Today.AddDays(-(int)DateTime.Today.DayOfWeek + (int)DayOfWeek.Tuesday);

Answer 3

もう少しデフォルト値が設定され、文化を意識:

System.Globalization.CultureInfo ci = 
    System.Threading.Thread.CurrentThread.CurrentCulture;
DayOfWeek fdow = ci.DateTimeFormat.FirstDayOfWeek;
DayOfWeek today = DateTime.Now.DayOfWeek;
DateTime sow = DateTime.Now.AddDays(-(today - fdow)).Date;

Answer 4

を使用 を堪能したDateTime:

var monday = DateTime.Now.Previous(DayOfWeek.Monday);
var sunday = DateTime.Now.Previous(DayOfWeek.Sunday);

Answer 5

醜いものでは少なくとも、右豊

開始の週間の設定によりシステム

    public static DateTime FirstDateInWeek(this DateTime dt)
    {
        while (dt.DayOfWeek != System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat.FirstDayOfWeek)
            dt = dt.AddDays(-1);
        return dt;
    }

な:

    public static DateTime FirstDateInWeek(this DateTime dt, DayOfWeek weekStartDay)
    {
        while (dt.DayOfWeek != weekStartDay)
            dt = dt.AddDays(-1);
        return dt;
    }

Answer 6

ましょうを組み合わせの文化-安全な答えの方に答え:

public static class DateTimeExtensions
{
    public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
    {
        System.Globalization.CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
        DayOfWeek fdow = ci.DateTimeFormat.FirstDayOfWeek;
        return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek- fdow));
    }
}

Answer 7

このビットのハッキングができます。DayOfWeek性のint(この列挙型であなたと配下のデータ型を変更でデフォルトはint)を使用する決定前の開始しました。

で、週に指定されたDayOfWeek enum開始日の日曜日でない場合減算1からこの価値だとどのように多くの日は、月曜日、現在の日付です。また地図の(0)に等しくなければな7といったものも1-7=-6の日曜日までの地図は、前月曜日-

DateTime now = DateTime.Now;
int dayOfWeek = (int)now.DayOfWeek;
dayOfWeek = dayOfWeek == 0 ? 7 : dayOfWeek;
DateTime startOfWeek = now.AddDays(1 - (int)now.DayOfWeek);

このコードの前の日曜日は簡単にいないためこの調整-

DateTime now = DateTime.Now;
int dayOfWeek = (int)now.DayOfWeek;
DateTime startOfWeek = now.AddDays(-(int)now.DayOfWeek);

Answer 8

これにより前日(い):

DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek, 0, 0, 0);

Answer 9

のための月曜日

DateTime startAtMonday = DateTime.Now.AddDays(DayOfWeek.Monday - DateTime.Now.DayOfWeek);

日曜日

DateTime startAtSunday = DateTime.Now.AddDays(DayOfWeek.Sunday- DateTime.Now.DayOfWeek);

Answer 10

using System;
using System.Globalization;

namespace MySpace
{
    public static class DateTimeExtention
    {
        // ToDo: Need to provide culturaly neutral versions.

        public static DateTime GetStartOfWeek(this DateTime dt)
        {
            DateTime ndt = dt.Subtract(TimeSpan.FromDays((int)dt.DayOfWeek));
            return new DateTime(ndt.Year, ndt.Month, ndt.Day, 0, 0, 0, 0);
        }

        public static DateTime GetEndOfWeek(this DateTime dt)
        {
            DateTime ndt = dt.GetStartOfWeek().AddDays(6);
            return new DateTime(ndt.Year, ndt.Month, ndt.Day, 23, 59, 59, 999);
        }

        public static DateTime GetStartOfWeek(this DateTime dt, int year, int week)
        {
            DateTime dayInWeek = new DateTime(year, 1, 1).AddDays((week - 1) * 7);
            return dayInWeek.GetStartOfWeek();
        }

        public static DateTime GetEndOfWeek(this DateTime dt, int year, int week)
        {
            DateTime dayInWeek = new DateTime(year, 1, 1).AddDays((week - 1) * 7);
            return dayInWeek.GetEndOfWeek();
        }
    }
}

Answer 11

けでは、なくてはならない、グローバリゼーションと可能を指定する週の開始曜日を通して

public static DateTime StartOfWeek ( this DateTime dt, DayOfWeek? firstDayOfWeek )
{
    DayOfWeek fdow;

    if ( firstDayOfWeek.HasValue  )
    {
        fdow = firstDayOfWeek.Value;
    }
    else
    {
        System.Globalization.CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
        fdow = ci.DateTimeFormat.FirstDayOfWeek;
    }

    int diff = dt.DayOfWeek - fdow;

    if ( diff < 0 )
    {
        diff += 7;
    }

    return dt.AddDays( -1 * diff ).Date;

}

Answer 12

var now = System.DateTime.Now;

var result = now.AddDays(-((now.DayOfWeek - System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat.FirstDayOfWeek + 7) % 7)).Date;

Answer 13

これだけ深夜初の日曜日が週の

DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek, t.Hour, t.Minute, t.Second);

これにより、最初の月曜日の深夜:

DateTime t = DateTime.Now;
t -= new TimeSpan ((int) t.DayOfWeek - 1, t.Hour, t.Minute, t.Second);

Answer 14

してもいいのですが、このクライアントまで、フルのc#.このコードできるのも初日と最終日を指定のもの。この日は初日と土曜日は最終日が設定できるものに従って文化

DateTime firstDate = GetFirstDateOfWeek(DateTime.Parse("05/09/2012").Date,DayOfWeek.Sunday);
DateTime lastDate = GetLastDateOfWeek(DateTime.Parse("05/09/2012").Date, DayOfWeek.Saturday);

public static DateTime GetFirstDateOfWeek(DateTime dayInWeek, DayOfWeek firstDay)
{
    DateTime firstDayInWeek = dayInWeek.Date;
    while (firstDayInWeek.DayOfWeek != firstDay)
        firstDayInWeek = firstDayInWeek.AddDays(-1);

    return firstDayInWeek;
}
public static DateTime GetLastDateOfWeek(DateTime dayInWeek, DayOfWeek firstDay)
{
    DateTime lastDayInWeek = dayInWeek.Date;
    while (lastDayInWeek.DayOfWeek != firstDay)
        lastDayInWeek = lastDayInWeek.AddDays(1);

    return lastDayInWeek;
}

Answer 15

したがなかった問題を解決すると週における月曜に与えてくれて、来週月曜日。思修で少しやっとこのコード:

int delta = DayOfWeek.Monday - DateTime.Now.DayOfWeek;
DateTime monday = DateTime.Now.AddDays(delta == 1 ? -6 : delta);
return monday;

Answer 16

以下のメソッドは返却したDateTimeしています。渡true日曜日の曜日の場合は、falseの場合のための月曜日

private DateTime getStartOfWeek(bool useSunday)
{
    DateTime now = DateTime.Now;
    int dayOfWeek = (int)now.DayOfWeek;

    if(!useSunday)
        dayOfWeek--;

    if(dayOfWeek < 0)
    {// day of week is Sunday and we want to use Monday as the start of the week
    // Sunday is now the seventh day of the week
        dayOfWeek = 6;
    }

    return now.AddDays(-1 * (double)dayOfWeek);
}

Answer 17

の例です。を使用してください"CurrentCulture"週の開始曜日および配列か知る必要のある正確なDaynumber..これらの私の最初の拡張:

public static class DateTimeExtensions
{
    //http://stackoverflow.com/questions/38039/how-can-i-get-the-datetime-for-the-start-of-the-week
    //http://stackoverflow.com/questions/1788508/calculate-date-with-monday-as-dayofweek1
    public static DateTime StartOfWeek(this DateTime dt)
    {
        //difference in days
        int diff = (int)dt.DayOfWeek - (int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek; //sunday=always0, monday=always1, etc.

        //As a result we need to have day 0,1,2,3,4,5,6 
        if (diff < 0)
        {
            diff += 7;
        }
        return dt.AddDays(-1 * diff).Date;
    }

    public static int DayNoOfWeek(this DateTime dt)
    {
        //difference in days
        int diff = (int)dt.DayOfWeek - (int)CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek; //sunday=always0, monday=always1, etc.

        //As a result we need to have day 0,1,2,3,4,5,6 
        if (diff < 0)
        {
            diff += 7;
        }
        return diff + 1; //Make it 1..7
    }
}

Answer 18

ないの答えは正しくなった。私はペーストもこちらの場合には誰もそれを必要としています。次のコードの作品はその週の開始曜日は月曜日や日曜日には、地下鉄からも近くて便利。

public static class DateTimeExtension
{
  public static DateTime GetFirstDayOfThisWeek(this DateTime d)
  {
    CultureInfo ci = System.Threading.Thread.CurrentThread.CurrentCulture;
    var first = (int)ci.DateTimeFormat.FirstDayOfWeek;
    var current = (int)d.DayOfWeek;

    var result = first <= current ?
      d.AddDays(-1 * (current - first)) :
      d.AddDays(first - current - 7);

    return result;
  }
}

class Program
{
  static void Main()
  {
    System.Threading.Thread.CurrentThread.CurrentCulture = CultureInfo.GetCultureInfo("en-US");
    Console.WriteLine("Current culture set to en-US");
    RunTests();
    Console.WriteLine();
    System.Threading.Thread.CurrentThread.CurrentCulture = CultureInfo.GetCultureInfo("da-DK");
    Console.WriteLine("Current culture set to da-DK");
    RunTests();
    Console.ReadLine();
  }

  static void RunTests()
  {
    Console.WriteLine("Today {1}: {0}", DateTime.Today.Date.GetFirstDayOfThisWeek(), DateTime.Today.Date.ToString("yyyy-MM-dd"));
    Console.WriteLine("Saturday 2013-03-02: {0}", new DateTime(2013, 3, 2).GetFirstDayOfThisWeek());
    Console.WriteLine("Sunday 2013-03-03: {0}", new DateTime(2013, 3, 3).GetFirstDayOfThisWeek());
    Console.WriteLine("Monday 2013-03-04: {0}", new DateTime(2013, 3, 4).GetFirstDayOfThisWeek());
  }
}

Answer 19

Moduloクライアントまで、フルのC#の作品に悪い影響-1mod7（6、c#-1を返します) なので---"oneliner"ソリューションにこのようなものです:)

private static DateTime GetFirstDayOfWeek(DateTime date)
    {
        return date.AddDays(-(((int)date.DayOfWeek - 1) - (int)Math.Floor((double)((int)date.DayOfWeek - 1) / 7) * 7));
    }

Answer 20

同じ末週間のスタイル@コンパイルすので解答):

    public static DateTime EndOfWeek(this DateTime dt)
    {
        int diff = 7 - (int)dt.DayOfWeek;

        diff = diff == 7 ? 0 : diff;

        DateTime eow = dt.AddDays(diff).Date;

        return new DateTime(eow.Year, eow.Month, eow.Day, 23, 59, 59, 999) { };
    }

Answer 21

ステップ1：静解析スタディを作成しクラス

  public static class TIMEE
{
    public static DateTime StartOfWeek(this DateTime dt, DayOfWeek startOfWeek)
    {
        int diff = (7 + (dt.DayOfWeek - startOfWeek)) % 7;
        return dt.AddDays(-1 * diff).Date;
    }
    public static DateTime EndOfWeek(this DateTime dt, DayOfWeek startOfWeek)
    {
        int diff = (7 - (dt.DayOfWeek - startOfWeek)) % 7;
        return dt.AddDays(1 * diff).Date;
    }
}

Step2:このクラスを使用する車両の開始と終了の日の週

 DateTime dt =TIMEE.StartOfWeek(DateTime.Now ,DayOfWeek.Monday);
        DateTime dt1 = TIMEE.EndOfWeek(DateTime.Now, DayOfWeek.Sunday);

Answer 22

きく使える優れもの 傘図書館:

using nVentive.Umbrella.Extensions.Calendar;
DateTime beginning = DateTime.Now.BeginningOfWeek();

しかし、その い いように保存し月曜日の週の開始曜日の物件 nVentive.Umbrella.Extensions.Calendar.DefaultDateTimeCalendarExtensions.WeekBeginsOnし、以前の局在解なものだけではありませんう？

編集:見での質問なんだかとってもおいしそうに傘が実際に働いています：

// Or DateTime.Now.PreviousDay(DayOfWeek.Monday)
DateTime monday = DateTime.Now.PreviousMonday(); 
DateTime sunday = DateTime.Now.PreviousSunday();

このことは特筆に値する要求がある場合は、前の月曜日、月曜日までの七日間です。ものについても同様のことがご利用の場合 BeginningOfWeek, るように思わbug:(.

Answer 23

この戻りますの初めの週末週間の日程:

    private string[] GetWeekRange(DateTime dateToCheck)
    {
        string[] result = new string[2];
        TimeSpan duration = new TimeSpan(0, 0, 0, 0); //One day 
        DateTime dateRangeBegin = dateToCheck;
        DateTime dateRangeEnd = DateTime.Today.Add(duration);

        dateRangeBegin = dateToCheck.AddDays(-(int)dateToCheck.DayOfWeek);
        dateRangeEnd = dateToCheck.AddDays(6 - (int)dateToCheck.DayOfWeek);

        result[0] = dateRangeBegin.Date.ToString();
        result[1] = dateRangeEnd.Date.ToString();
        return result;

    }

掲載している完了コード計算の開始/終週、月、四半期、年間を自分のブログ ZamirsBlog

Answer 24

    namespace DateTimeExample
    {
        using System;

        public static class DateTimeExtension
        {
            public static DateTime GetMonday(this DateTime time)
            {
                if (time.DayOfWeek != DayOfWeek.Monday)
                    return GetMonday(time.AddDays(-1)); //Recursive call

                return time;
            }
        }

        internal class Program
        {
            private static void Main()
            {
                Console.WriteLine(DateTime.Now.GetMonday());
                Console.ReadLine();
            }
        }
    } 

Answer 25

こちらを組み合わせの答えなのです。この拡張手法では文化を渡された場合には渡され、現在の文化を使用します。これまでで最大の柔軟性と再利用されます。

/// <summary>
/// Gets the date of the first day of the week for the date.
/// </summary>
/// <param name="date">The date to be used</param>
/// <param name="cultureInfo">If none is provided, the current culture is used</param>
/// <returns>The date of the beggining of the week based on the culture specifed</returns>
public static DateTime StartOfWeek(this DateTime date, CultureInfo cultureInfo=null) =>         
             date.AddDays(-1 * (7 + (date.DayOfWeek - (cultureInfo??CultureInfo.CurrentCulture).DateTimeFormat.FirstDayOfWeek)) % 7).Date;

使用例:

public static void TestFirstDayOfWeekExtension() {          
        DateTime date = DateTime.Now;
        foreach(System.Globalization.CultureInfo culture in CultureInfo.GetCultures(CultureTypes.UserCustomCulture | CultureTypes.SpecificCultures)) {
            Console.WriteLine($"{culture.EnglishName}: {date.ToShortDateString()} First Day of week: {date.StartOfWeek(culture).ToShortDateString()}");
        }
    }

Answer 26

したい場合は土曜日又は日曜日又は日曜ものを超えない現在の週間（土-日）ういう真っ当な定食を楽しむ事がでこの作品のコードです。

public static DateTime GetDateInCurrentWeek(this DateTime date, DayOfWeek day)
{
    var temp = date;
    var limit = (int)date.DayOfWeek;
    var returnDate = DateTime.MinValue;

    if (date.DayOfWeek == day) return date;

    for (int i = limit; i < 6; i++)
    {
        temp = temp.AddDays(1);

        if (day == temp.DayOfWeek)
        {
            returnDate = temp;
            break;
        }
    }
    if (returnDate == DateTime.MinValue)
    {
        for (int i = limit; i > -1; i++)
        {
            date = date.AddDays(-1);

            if (day == date.DayOfWeek)
            {
                returnDate = date;
                break;
            }
        }
    }
    return returnDate;
}

Answer 27

いつ-ライナー:車との違い、現在の文化の開始日と、現在の日を減算の日数から当日

var weekStartDate = DateTime.Now.AddDays(-((int)now.DayOfWeek - (int)DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek));

Answer 28

   d = DateTime.Now;
            int dayofweek =(int) d.DayOfWeek;
            if (dayofweek != 0)
            {
                d = d.AddDays(1 - dayofweek);
            }
            else { d = d.AddDays(-6); }

Answer 29

public static System.DateTime getstartweek()
{
    System.DateTime dt = System.DateTime.Now;
    System.DayOfWeek dmon = System.DayOfWeek.Monday;
    int span = dt.DayOfWeek - dmon;
    dt = dt.AddDays(-span);
    return dt;
}