How can I form this DateTime logic to increase the current time by 45 minutes

Question

I am to fill a ddl at run time.

What I actually need to do is pick up the current time from the system (in 24-hour format). Then I need to round it up to a 15 min slot, so if the time is 13:23 it will become 13:30; if it is 13:12 then it should become 13:15.

Then I want to add 45 minutes to it, and 13:15 becomes 14:00.

I am trying to achieve it like this

DateTime d = DateTime.Now;
string hr = d.ToString("HH:mm");
string mi = d.ToString("mm");

Could somebody tell, either I have to write all logic or DateTime can provide some feature to format it like this?

This should get you started http://stackoverflow.com/questions/7029353/c-sharp-round-up-time-to-nearest-x-minutes , once you get the rounding part you have `AddMinutes` available — V4Vendetta, Apr 04 '13 at 09:03

Peter · Answer 1 · 2013-04-04T09:08:39.803

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        DateTime d = DateTime.Now;

        //Add your 45 minutes
        d = d.AddMinutes(45);

        //Add minutes to the next quarter of an hour 
        d = d.AddMinutes((15 - d.TimeOfDay.Minutes % 15) % 15);

        //Show your result
        string hr = d.ToString("HH:mm");
        string mi = d.ToString("mm");

edited Apr 04 '13 at 09:08

answered Apr 04 '13 at 09:02

Peter

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Your code to add the minutes to the next quarter of an hour is faulty. When the minute amount is 0 it will still add 15, despite being a quarter already. – JustAnotherUserYouMayKnow Apr 04 '13 at 09:11
Thank you for correcting it. That's even better than my solution. :-) – JustAnotherUserYouMayKnow Apr 04 '13 at 09:14

Mike Perrenoud · Accepted Answer · 2013-04-04T09:11:07.667

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I think this should do the trick for you:

var d = DateTime.Now;
d = d.AddSeconds(-d.Seconds).AddMilliseconds(-d.Milliseconds)

if (d.Minute < 15) { d.AddMinutes(15 - d.Minute); }
else if (d.Minute < 30) { d = d.AddMinutes(30 - d.Minute); }
else if (d.Minute < 45) { d = d.AddMinutes(45 - d.Minute); }
else if (d.Minute < 60) { d = d.AddMinutes(60 - d.Minute); }

d = d.AddMinutes(45);

edited Apr 04 '13 at 09:11

answered Apr 04 '13 at 09:04

Mike Perrenoud

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Maybe first a `d = d.AddSeconds(-d.Seconds).AddMilliseconds(-d.Milliseconds)` to reset those parts? – Hans Keﬆing Apr 04 '13 at 09:09
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@HansKesting, that would probably be a good reset. I'll add that, thanks for the idea! – Mike Perrenoud Apr 04 '13 at 09:10

score 1 · Answer 3 · answered Apr 04 '13 at 09:04

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DateTime in C# has a function for adding any increment to the current DateTime object. Here is a reference to the specific function for minutes.

answered Apr 04 '13 at 09:04

Elad Lachmi

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Arie · Answer 4 · 2013-04-04T09:16:47.803

1

DateTime d = DateTime.Now;

DateTime rounded;
if(d.Minute % 15 ==0)rounded = d;
else DateTime rounded = d.AddMinutes(15 - d.Minute % 15);

Console.WriteLine("{0:HH:mm}",rounded);

edited Apr 04 '13 at 09:16

answered Apr 04 '13 at 09:08

Arie

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Wouldn't that round 15 to 30? – George Duckett Apr 04 '13 at 09:13

How can I form this DateTime logic to increase the current time by 45 minutes

4 Answers4