I try to popup a msgbox that shows the months and years of the given dates for example
my input is:
7/2012 and 2/2013
and the output should be:
7/2012,8/2012,9/2012,10/2012,11/2012,12/2012,1/2013,2/2013
I wrote:
string datePart1;
string datePart2;
string[] date1 = new string[] { "" };
string[] date2 = new string[] { "" };
private void button1_Click(object sender, EventArgs e)
{
DateTime endDate = new DateTime(2013, 2, 1); // i will be having the date time as a variable from a textbox
DateTime begDate = new DateTime(2012, 7, 1); // i will be having the date time as a variable from a text box
int year, month;
if (endDate.Month - begDate.Month < 0)
{
month = (endDate.Month - begDate.Month) + 12;
endDate = new DateTime(endDate.Year - 1, endDate.Month, endDate.Day);
}
else
month = endDate.Month - begDate.Month;
year = endDate.Year - begDate.Year;
The above code calculates the time difference, but my attempts at outputting haven't worked.
Here's a sample to get you started.
It provides a handy MonthsInRange() method which returns a sequence of all the months in the specified range. You can then format the returned dates using "M\\/yyyy" (see below) to output the required format. (Note: That's not a letter V, it's a backslash followed by a forward slash!)
See Custom Date and Time Format Strings for an explanation of the format string.
using System;
using System.Collections.Generic;
namespace Demo
{
public static class Program
{
static void Main(string[] args)
{
DateTime endDate = new DateTime(2013, 2, 1);
DateTime begDate = new DateTime(2012, 7, 1);
foreach (DateTime date in MonthsInRange(begDate, endDate))
{
Console.WriteLine(date.ToString("M\\/yyyy"));
}
}
public static IEnumerable<DateTime> MonthsInRange(DateTime start, DateTime end)
{
for (DateTime date = start; date <= end; date = date.AddMonths(1))
{
yield return date;
}
}
}
}
Why "M\\/yyyy" and not just "M/yyyy"?
This is because the "/" character in a DateTime format string will be interpreted as the "date separator", not a literal "/". In some locales, this will come out as "." and not "/".
To fix this, we need to escape it with a "\" character. However, we can't just use a single "\" because C# itself will interpret that as an escape character, and will use it to escape the following character. The C# escape sequence for a literal "\" is "\\", which is why we have to put "\\/" and not just "\/".
Alternatively you can turn of escaping of "\" characters by prefixing the string with an # character, like so:
#"M/yyyy"
You can use whichever you prefer.
Since you're not guaranteed to have dates with the same day, you can use this code which creates new dates that only consider the first of the month.
static IEnumerable<string> InclusiveMonths(DateTime start, DateTime end)
{
// copies to ensure the same day.
var startMonth = new DateTime(start.Year, start.Month, 1);
var endMonth = new DateTime(end.Year, end.Month, 1);
for (var current = startMonth; current <= endMonth; current = current.AddMonths(1))
yield return current.ToString("M/yyyy");
}
// usage
foreach (var mmyyyy in InclusiveMonths(begDate, endDate))
{
Console.WriteLine(mmyyyy);
}
var allMonths = string.Join(", ", InclusiveMonths(begDate, endDate));
Look into using the TimeSpan structure, it'll help you achieve your goal a lot faster.
http://msdn.microsoft.com/en-us/library/system.timespan.aspx
You may use
TimeSpan dateDifference = endDate - begDate;
year = dateDifference.Days / 365;
month = dateDifference.Days / 30;
Edit:
I forgot TimeSpan does not feature Year or Month, sorry :(
How can I change only the time in my DateTime variable "s"?
DateTime s = some datetime;
You can't change a DateTime value - it's immutable. However, you can change the variable to have a new value. The easiest way of doing that to change just the time is to create a TimeSpan with the relevant time, and use the DateTime.Date property:
DateTime s = ...;
TimeSpan ts = new TimeSpan(10, 30, 0);
s = s.Date + ts;
s will now be the same date, but at 10.30am.
Note that DateTime disregards daylight saving time transitions, representing "naive" Gregorian time in both directions (see Remarks section in the DateTime docs). The only exceptions are .Now and .Today: they retrieve current system time which reflects these events as they occur.
This is the kind of thing which motivated me to start the Noda Time project, which is now production-ready. Its ZonedDateTime type is made "aware" by linking it to a tz database entry.
Alright I'm diving in with my suggestion, an extension method:
public static DateTime ChangeTime(this DateTime dateTime, int hours, int minutes, int seconds, int milliseconds)
{
return new DateTime(
dateTime.Year,
dateTime.Month,
dateTime.Day,
hours,
minutes,
seconds,
milliseconds,
dateTime.Kind);
}
Then call:
DateTime myDate = DateTime.Now.ChangeTime(10,10,10,0);
It's important to note that this extension returns a new date object, so you can't do this:
DateTime myDate = DateTime.Now;
myDate.ChangeTime(10,10,10,0);
But you can do this:
DateTime myDate = DateTime.Now;
myDate = myDate.ChangeTime(10,10,10,0);
s = s.Date.AddHours(x).AddMinutes(y).AddSeconds(z);
In this way you preserve your date, while inserting a new hours, minutes and seconds part to your liking.
one liner
var date = DateTime.Now.Date.Add(new TimeSpan(4, 30, 0));
would bring back todays date with a time of 4:30:00, replace DateTime.Now with any date object
DateTime is an immutable type, so you can't change it.
However, you can create a new DateTime instance based on your previous instance. In your case, it sounds like you need the Date property, and you can then add a TimeSpan that represents the time of day.
Something like this:
var newDt = s.Date + TimeSpan.FromHours(2);
If you already have the time stored in another DateTime object you can use the Add method.
DateTime dateToUse = DateTime.Now();
DateTime timeToUse = new DateTime(2012, 2, 4, 10, 15, 30); //10:15:30 AM
DateTime dateWithRightTime = dateToUse.Date.Add(timeToUse.TimeOfDay);
The TimeOfDay property is a TimeSpan object and can be passed to the Add method. And since we use the Date property of the dateToUse variable we get just the date and add the time span.
Simplest solution :
DateTime s = //some Datetime that you want to change time for 8:36:44 ;
s = new DateTime(s.Year, s.Month, s.Day, 8, 36, 44);
And if you need a specific Date and Time Format :
s = new DateTime(s.Year, s.Month, s.Day, 8, 36, 44).ToString("yyyy-MM-dd h:mm:ss");
You can assign an initial value to a new DateTime value in many different ways:
Extension Method
Extension method DateTime
public static DateTime ChangeTime(this DateTime dateTime, int hours, int minutes, int seconds = default, int milliseconds = default)
{
return new DateTime(dateTime.Year, dateTime.Month, dateTime.Day, hours, minutes, seconds, milliseconds, dateTime.Kind);
}
then using ChangeTime:
DateTime datetime = DateTime.Now; //Your DateTime
datetime = datetime.ChangeTime(12, 20, 10);
using the Add methods
DateTime datetime = DateTime.Now; //Your DateTime
datetime = datetime.Date.AddHours(12).AddMinutes(20).AddSeconds(10);
using the Timespan
DateTime datetime = DateTime.Now; //Your DateTime
datetime = datetime.Date.Add(new TimeSpan(12, 20, 10));
using initial value
DateTime datetime = DateTime.Now;
datetime = new DateTime(datetime.Year, datetime.Month, datetime.Day, 12, 20, 10);
DateTime ts = DateTime.Now;
ts = new DateTime ( ts.Year, ts.Month, ts.Day, 0, 0, 0 ) ;
Console.WriteLine ( "Today = " + ts.ToString("M/dd/yy HH:mm:ss") ) ;
Executed:
Today = 9/04/15 00:00:00
Happened upon this post as I was looking for the same functionality this could possibly do what the guy wanted. Take the original date and replace the time part
DateTime dayOpen = DateTime.Parse(processDay.ToShortDateString() + " 05:00 AM");
Adding .Date to your date sets it to midnight (00:00).
MyDate.Date
Note The equivavalent SQL is CONVERT(DATETIME, CONVERT(DATE, #MyDate))
What makes this method so good is that it's both quick to type and easy to read. A bonus is that there is no conversion from strings.
I.e. To set today's date to 23:30, use:
DateTime.Now.Date.AddHours(23).AddMinutes(30)
You can of course replace DateTime.Now or MyDate with any date of your choice.
Since DateTime is immutable, a new instance has to be created when a date component needs to be changed. Unfortunately, there is no built-in functionality to set individual components of a DateTime instance.
Using the following extension methods
public static DateTime SetPart(this DateTime dateTime, int? year, int? month, int? day, int? hour, int? minute, int? second)
{
return new DateTime(
year ?? dateTime.Year,
month ?? dateTime.Month,
day ?? dateTime.Day,
hour ?? dateTime.Hour,
minute ?? dateTime.Minute,
second ?? dateTime.Second
);
}
public static DateTime SetYear(this DateTime dateTime, int year)
{
return dateTime.SetPart(year, null, null, null, null, null);
}
public static DateTime SetMonth(this DateTime dateTime, int month)
{
return dateTime.SetPart(null, month, null, null, null, null);
}
public static DateTime SetDay(this DateTime dateTime, int day)
{
return dateTime.SetPart(null, null, day, null, null, null);
}
public static DateTime SetHour(this DateTime dateTime, int hour)
{
return dateTime.SetPart(null, null, null, hour, null, null);
}
public static DateTime SetMinute(this DateTime dateTime, int minute)
{
return dateTime.SetPart(null, null, null, null, minute, null);
}
public static DateTime SetSecond(this DateTime dateTime, int second)
{
return dateTime.SetPart(null, null, null, null, null, second);
}
you can set individual DateTime components like
var now = DateTime.Now;
now.SetSecond(0);
When you construct your DateTime object, use a constructor that allows you to specify time:
var myDateTime = new DateTime(2000, 01, 01, 13, 37, 42); // 2000-01-01 13:37:42
If you already have a DateTime object and wish to change the time, uou can add minutes, hours or seconds to your DateTime using simple methods:
var myDateTime = new DateTime(2000, 01, 01); // 2000-01-01 00:00:00
myDateTime = myDateTime.AddHours(13); // 2000-01-01 13:00:00
myDateTime = myDateTime.AddMinutes(37); // 2000-01-01 13:37:00
myDateTime = myDateTime.AddSecounds(42); // 2000-01-01 13:37:42
Notice how we have to "save" the result from each method call to the myDateTime variable. This is because the DateTime is immutable, and its methods simply create new instances with the extra hours/minutes/seconds added.
If you need to add both hours and minutes (and/or seconds) and the same time, you can simplify the code by adding a TimeSpan to the original DateTime instead:
var myDateTime = new DateTime(2000, 01, 01); // 2000-01-01 00:00:00
myDateTime += new TimeSpan(13, 37, 42); // 2000-01-01 13:37:42
If you want to set absolute hours/minues/seconds, rather than adding to the existing values, you can use the aforementioned DateTime constructor, and reuse values for year/month/day from earlier:
myDateTime = new DateTime(myDateTime.Year, myDateTime.Month, myDateTime.Day,
20, 33, 19) // 2000-01-01 20:33:19
In fact, you can't change the time once it's created.
But you can create it easily with many constructors:
https://learn.microsoft.com/en-us/dotnet/api/system.datetime.-ctor?view=netframework-4.7.2
For example, if you want to create a DateTime changing Seconds, you can just do this:
DateTime now = DateTime.Now;
DateTime secondschanged = new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, yourseconds);
If you have a DateTime like 2014/02/05 18:19:51 and want just 2014/02/05, you can do that:
_yourDateTime = new DateTime(_yourDateTime.Year, _yourDateTime.Month, _yourDateTime.Day)
Use Date.Add and add a New TimeSpan with the new time you want to add
DateTime dt = DateTime.Now
dt.Date.Add(new TimeSpan(12,15,00))
int year = 2012;
int month = 12;
int day = 24;
int hour = 0;
int min = 0;
int second = 23;
DateTime dt = new DateTime(year, month, day, hour, min, second);
To set end of a day:
date = new DateTime(date.Year, date.Month, date.Day, 23, 59, 59);
Here is a method you could use to do it for you, use it like this
DateTime newDataTime = ChangeDateTimePart(oldDateTime, DateTimePart.Seconds, 0);
Here is the method, there is probably a better way, but I just whipped this up:
public enum DateTimePart { Years, Months, Days, Hours, Minutes, Seconds };
public DateTime ChangeDateTimePart(DateTime dt, DateTimePart part, int newValue)
{
return new DateTime(
part == DateTimePart.Years ? newValue : dt.Year,
part == DateTimePart.Months ? newValue : dt.Month,
part == DateTimePart.Days ? newValue : dt.Day,
part == DateTimePart.Hours ? newValue : dt.Hour,
part == DateTimePart.Minutes ? newValue : dt.Minute,
part == DateTimePart.Seconds ? newValue : dt.Second
);
}
I have just come across this post because I had a similar issue whereby I wanted to set the time for an Entity Framework object in MVC that gets the date from a view (datepicker) so the time component is 00:00:00 but I need it to be the current time. Based on the answers in this post I came up with:
myEntity.FromDate += DateTime.Now.TimeOfDay;
//The fastest way to copy time
DateTime justDate = new DateTime(2011, 1, 1); // 1/1/2011 12:00:00AM the date you will be adding time to, time ticks = 0
DateTime timeSource = new DateTime(1999, 2, 4, 10, 15, 30); // 2/4/1999 10:15:30AM - time tick = x
justDate = new DateTime(justDate.Date.Ticks + timeSource.TimeOfDay.Ticks);
Console.WriteLine(justDate); // 1/1/2011 10:15:30AM
Console.Read();
DateTime s;
//s = datevalue
s = s.AddMilliseconds(10);
s = s.AddMinutes(10);
s = s.AddSeconds(10);
s = s.AddHours(10);
you could add +ve/-ve values in parameter.
s.Add(new TimeSpan(1, 1, 1));
Doesn't that fix your problems??
Dateime dt = DateTime.Now;
dt = dt.AddSeconds(10);
I prefer this:
DateTime s = //get some datetime;
s = new DateTime(s.Year, s.Month,s.Day,s.Hour,s.Minute,0);
Using an extencion to DateTime:
public enum eTimeFragment
{
hours,
minutes,
seconds,
milliseconds
}
public static DateTime ClearTimeFrom(this DateTime dateToClear, eTimeFragment etf)
{
DateTime dtRet = dateToClear;
switch (etf)
{
case eTimeFragment.hours:
dtRet = dateToClear.Date;
break;
case eTimeFragment.minutes:
dtRet = dateToClear.AddMinutes(dateToClear.Minute * -1);
dtRet = dtRet.ClearTimeFrom(eTimeFragment.seconds);
break;
case eTimeFragment.seconds:
dtRet = dateToClear.AddSeconds(dateToClear.Second * -1);
dtRet = dtRet.ClearTimeFrom(eTimeFragment.milliseconds);
break;
case eTimeFragment.milliseconds:
dtRet = dateToClear.AddMilliseconds(dateToClear.Millisecond * -1);
break;
}
return dtRet;
}
Use like this:
Console.WriteLine (DateTime.Now.ClearTimeFrom(eTimeFragment.hours))
this has to return:
2016-06-06 00:00:00.000
What's wrong with DateTime.AddSeconds method where you can add or substract seconds?
Try this one
var NewDate = Convert.ToDateTime(DateTime.Now.ToString("dd/MMM/yyyy")+" "+"10:15 PM")/*Add your time here*/;
The best solution is:
currdate.AddMilliseconds(currdate.Millisecond * -1).AddSeconds(currdate.Second * -1).AddMinutes(currdate.Minute * -1).AddHours(currdate.Hour * -1);
here is a ghetto way, but it works :)
DateTime dt = DateTime.Now; //get a DateTime variable for the example
string newSecondsValue = "00";
dt = Convert.ToDateTime(dt.ToString("MM/dd/yyyy hh:mm:" + newSecondsValue));
In my C# app, I pass a string variable that is of format yyyymmdd-yyyymmdd that represents a from and to date. I want to get the start and end times for these dates respectively. Currently I have the below code but was wondering if there was more of an elegant solution?
So for pdr = 20090521-20090523 would get "20090521 00:00:00" and "20090523 23:59:59"
private void ValidateDatePeriod(string pdr, out DateTime startDate,
out DateTime endDate)
{
string[] dates = pdr.Split('-');
if (dates.Length != 2)
{
throw new Exception("Date period is of incorrect format");
}
if (dates[0].Length != 8 || dates[1].Length != 8)
{
throw new Exception("Split date periods are of incorrect format");
}
startDate = DateTime.ParseExact(dates[0] + " 00:00:00",
"yyyyMMdd HH:mm:ss", null);
endDate = DateTime.ParseExact(dates[1] + "23:59:59",
"yyyyMMdd HH::mm:ss", null);
}
I am surprised to see how an incorrect answer received so many upvotes:
The correct version would be as follows:
public static DateTime StartOfDay(this DateTime theDate)
{
return theDate.Date;
}
public static DateTime EndOfDay(this DateTime theDate)
{
return theDate.Date.AddDays(1).AddTicks(-1);
}
You could define two extension methods somewhere, in a utility class like so :
public static DateTime EndOfDay(this DateTime date)
{
return new DateTime(date.Year, date.Month, date.Day, 23, 59, 59, 999);
}
public static DateTime StartOfDay(this DateTime date)
{
return new DateTime(date.Year, date.Month, date.Day, 0, 0, 0, 0);
}
And then use them in code like so :
public DoSomething()
{
DateTime endOfThisDay = DateTime.Now.EndOfDay();
}
If you are only worried about .Net precision...
startDate = DateTime.ParseExact(dates[0], "yyyyMMdd");
endDate = DateTime.ParseExact(dates[1], "yyyyMMdd").AddTicks(-1).AddDays(1);
You really don't need to concatenate extra values onto the string for the time portion.
As an addendum, if you are using this for a query against, for example, a database...
startDate = DateTime.ParseExact(dates[0], "yyyyMMdd");
endDate = DateTime.ParseExact(dates[1], "yyyyMMdd").AddDays(1);
With a query of...
WHERE "startDate" >= #startDate AND "endDate" < #endDate
Then the precision issues noted in the comments won't really matter. The endDate in this case would not be part of the range, but the outside boundary.
The DateTime object has a property called Date which will return just the date portion. (The time portion is defaulted to 12:00 am).
I would recommend as a more elegant solution (IMHO) that if you want to allow any datetime on the last day, then you add 1 day to the date, and compare to allow times greater than or equal to the start date, but strictly less than the end date (plus 1 day).
// Calling code. beginDateTime and endDateTime are already set.
// beginDateTime and endDateTime are inclusive.
// targetDateTime is the date you want to check.
beginDateTime = beginDateTime.Date;
endDateTime = endDateTime.Date.AddDays(1);
if ( beginDateTime <= targetDateTime &&
targetDateTime < endDateTime )
// Do something.
public static class DateTimeExtension {
public static DateTime StartOfTheDay(this DateTime d) => new DateTime(d.Year, d.Month, d.Day, 0, 0,0);
public static DateTime EndOfTheDay(this DateTime d) => new DateTime(d.Year, d.Month, d.Day, 23, 59,59);
}
I use the following in C#
public static DateTime GetStartOfDay(DateTime dateTime)
{
return new DateTime(dateTime.Year, dateTime.Month, dateTime.Day, 0, 0, 0, 0);
}
public static DateTime GetEndOfDay(DateTime dateTime)
{
return new DateTime(dateTime.Year, dateTime.Month, dateTime.Day, 23, 59, 59, 999);
}
Then in MS SQL I do the following:
if datepart(ms, #dateEnd) = 0
set #dateEnd = dateadd(ms, -3, #dateEnd)
This will result in MS SQL time of 23:59:59.997 which is the max time before becoming the next day.
You could simply use:
new DateTime(dateTime.Year, dateTime.Month, dateTime.Day, 23, 59, 59, 999);
Which will work in MS SQL, but this is not as accurate in .Net side.
That's pretty much what I would do, with some small tweaks (really no big deal, just nitpicking):
The TryParse()/TryParseExact() methods should be used which return false instead of throwing exceptions.
FormatException is more specific than Exception
No need to check for Length == 8, because ParseExact()/TryParseExact() will do this
"00:00:00" and "23:59:59" are not needed
return true/false is you were able to parse, instead of throwing an exception (remember to check value returned from this method!)
Code:
private bool ValidateDatePeriod(string pdr, out DateTime startDate,
out DateTime endDate)
{
string[] dates = pdr.Split('-');
if (dates.Length != 2)
{
return false;
}
// no need to check for Length == 8 because the following will do it anyway
// no need for "00:00:00" or "23:59:59" either, I prefer AddDays(1)
if(!DateTime.TryParseExact(dates[0], "yyyyMMdd", null, DateTimeStyles.None, out startDate))
return false;
if(!DateTime.TryParseExact(dates[1], "yyyyMMdd", null, DateTimeStyles.None, out endDate))
return false;
endDate = endDate.AddDays(1);
return true;
}
I think we're doing it wrong. There is no such thing as the end of the day. AddTick(-1) only works under the convention that there are no time intervals smaller than a tick. Which is implementation dependent. Admittedly the question comes with a reference implementation, namely the .Net Framework DateTime class, but still we should take this as a clue that the function we really want is not EndOfDay() but StartOfNextDay()
public static DateTime StartOfNextDay(this DateTime date)
{
return date.Date.AddDays(1);
}
The issue above regarding the few milliseconds can be resolved by querying the database with the next day's start date.
For example:
SELECT * FROM temp WHERE createdDate >= fromDate AND createdDate < toDate
Using the extension methods below you could set the from and to dates to:
DateTimeOffset fromDate = DateTimeOffset.UtcNow.StartOfDay();
DateTimeOffset toDate = DateTimeOffset.UtcNow.EndOfDay();
public static class DateExtentions
{
public static DateTimeOffset StartOfDay(this DateTimeOffset dateTime)
{
return new DateTimeOffset(dateTime.Year, dateTime.Month, dateTime.Day, 0, 0, 0, 0, dateTime.Offset);
}
public static DateTimeOffset EndOfDay(this DateTimeOffset dateTime)
{
return dateTime.StartOfDay().AddDays(1);
}
public static DateTimeOffset StartOfMonth(this DateTimeOffset dateTime)
{
return new DateTimeOffset(dateTime.Year, dateTime.Month, 1, 0, 0, 0, 0, dateTime.Offset);
}
public static DateTimeOffset EndOfMonth(this DateTimeOffset dateTime)
{
return dateTime.StartOfMonth().AddMonths(1);
}
public static DateTimeOffset StartOfYear(this DateTimeOffset dateTime)
{
return new DateTimeOffset(dateTime.Year, 1, 1, 0, 0, 0, 0, dateTime.Offset);
}
public static DateTimeOffset EndOfYear(this DateTimeOffset dateTime)
{
return dateTime.StartOfYear().AddYears(1);
}
}
For SQL Server (version 2008 R2 tested) this ranges works.
StarDate '2016-01-11 00:00:01.990'
EndDate '2016-01-19 23:59:59.990'
Seems like ticks is greater that the last second of day and automatically round to next day. So i test and works, i made a dummy table with two dates for check what values is sql server catching and inserting in the stored procedure those parameters.
In Java 8, you can do it using LocalDate as follows:
LocalDate localDateStart = LocalDate.now();
Date startDate = Date.from(localDateStart.atStartOfDay(ZoneId.systemDefault()).toInstant());
LocalDate localDateEnd = localDateStart.plusDays(1);
Date endDate = Date.from(localDateEnd.atStartOfDay(ZoneId.systemDefault()).toInstant());