Get range of days in a week given a certain day

Question

Suppose my input is March 31, 2015.
How would I be able to get the days of the week that March 31, 2015 is in?
In this case, it should output:
March 29, 2015-April 4, 2015

I found something similar here but it's not quite what I'm looking for as that one takes in the week number while my input is a date itself.

One thing you can do is get the week number with the [`DayOfYear`](https://msdn.microsoft.com/en-us/library/system.datetime.dayofyear(v=vs.110).aspx) `/ 7` then use that solution. — ryanyuyu, Mar 31 '15 at 18:47
Perhaps check the `Date.getDay` method, and subtract X from Mar 31st until you get Sunday, then add Y until you get to Saturday? — sab669, Mar 31 '15 at 18:47

Ulugbek Umirov · Accepted Answer · 2015-03-31T18:52:49.140

7

DateTime date = new DateTime(2015, 3, 31);
DateTime weekFirstDay = date.AddDays(DayOfWeek.Sunday - date.DayOfWeek);
DateTime weekLastDay = weekFirstDay.AddDays(6);

edited Mar 31 '15 at 18:52

answered Mar 31 '15 at 18:48

Ulugbek Umirov

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isnt it `weekLastDay = weekFirstDay.AddDays(7);` – Ňɏssa Pøngjǣrdenlarp Mar 31 '15 at 18:50
1

technically I believe she wants `AddDays(6)` to match her output. But very efficient answer! – Jonesopolis Mar 31 '15 at 18:53
@Jonesy Yes, just noticed that as well. Thank you :) – Ulugbek Umirov Mar 31 '15 at 18:53
1

This is excellent! I didn't know about the `DayOfWeek` enumeration. Thanks! – Katie Mar 31 '15 at 18:54

Jeffrey Wieder · Answer 2 · 2015-03-31T18:53:03.797

4

Here is a way to get each value separately from a given DateTime

Week start:

    public static DateTime GetWeekStartDate(DateTime value)
    {
        return value.AddDays(-(int)value.DayOfWeek).Date;
    }

Week end:

    public static DateTime GetWeekEndDate(DateTime value)
    {
        return value.AddDays(6 - (int)value.DayOfWeek).Date;
    }

edited Mar 31 '15 at 18:53

answered Mar 31 '15 at 18:51

Jeffrey Wieder

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Did you miss something in your `GetWeekStartDate`? You just have a rogue `-` in `AddDays` – sab669 Mar 31 '15 at 18:52
2

Nope, that is correct, it turns the `DayOfWeek` `int` value to a negative value. – Jeffrey Wieder Mar 31 '15 at 18:53
1

OHHHH, duh that makes sense. You want Sunday so if it's Tuesday you're just subtracting that value. Nevermind! – sab669 Mar 31 '15 at 18:54

score 2 · Answer 3 · answered Mar 31 '15 at 18:59

DayOfWeek firstDayOfWeek = CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek;
DateTime startDate = DateTime.Now;

while (firstDayOfWeek != startDate.DayOfWeek)
{
   startDate = startDate.AddDays(-1);
}

DateTime firstDay = startDate.Date;
DateTime lastDay = startDate.AddDays(6);

Get range of days in a week given a certain day

3 Answers3