This is now bugging me , i have tried to fix it for the past hour but still no luck!
I hope some one could spot what i'm doing wrong . here is my code:
var maxDays = 30;
DateTime today = DateTime.Now; //todays date
DateTime lastAction = '2017-03-07 12:47:58.967';
double totalDays = (lastAction - today).TotalDays;
var days = Math.Round(totalDays);
if(days > maxDays)
{
//never hits this even though days is greater than max days ..i'm so confused
}
what am i doing wrong?
Duplicate problem as here:
C# Number of days between two dates problem
Timespan.TotalDays can be negative. So in your case it is almost guaranteed that lastAction - today will be a negative number, and so will always be less than 30.
If you only care about the absolute value of days, use Math.Abs otherwise re-arrange so that you are subtracting lastAction from today (today - lastAction).
Note that due to rounding, your condition will still not be triggered if there is less than 1 day difference.
Is it possible you are subtracting a larger value (today) from a small value (lastaction) which should result in a negative number making days negative?
That and you do need to do an explicit parse on the string to make it a date:
DateTime lastAction = DateTime.Parse("2017-03-07 12:47:58
.967");
Couple of things.
First you cant convert a string to DateTime like that. You should do something like this instead. DateTime lastAction = DateTime.Parse("2017-03-07 12:47:58.967");
Second, Just as #MikeS said, you are subtracting the lastAction from Today, which is resulting in a negative number (in this case its like -173). You should flip that statement. double totalDays = ( today - lastAction).TotalDays;
Your whole section should look something like this.
var maxDays = 30;
DateTime today = DateTime.Now; //todays date
DateTime lastAction = DateTime.Parse("2017-03-07 12:47:58.967");
double totalDays = ( today - lastAction).TotalDays;
var days = Math.Round(totalDays);
if (days > maxDays)
{
// now this is hit
}
Thanks for the help. I did something stupid .. I had
double totalDays = (lastAction - today).TotalDays; // returns -176
changed my code to:
double totalDays = (today - lastAction).TotalDays; //returns 176
Your first problem:
You didn't parse the string to DateTime.
DateTime lastAction = Convert.ToDateTime("2017-03-07 12:47:58.967");
Your second problem:
You were receiving a negative value, and checking if it's bigger.
var days = (Math.Round(totalDays)) * (-1);
Like this, it should work.
Related
I want get diffrences Day,Hour and Day between two days.
I use belowe Code :
DateTime LastDate = DateTime.Parse("2/12/2015 11:24:23 AM");
int differenceDay = DateTime.Now.Subtract(LastDate).Days;
int differenceHoure = DateTime.Now.Hour - LastDate.Hour;//returns -11
int differenceMinute = DateTime.Now.Minute - LastDate.Minute;
When I want get Hours its return mines (-11 e.t).
How can I get positive Diffrence Hour ?
anyone can you help me?
I want get Last Dat and show its by string how days afterd now.
You're subtracting component-wise (i.e. "this hour-of-day minus that hour-of-day, this minute-of-hour minus that minute-of-hour"). Don't do that - it won't work if the current hour-of-day is earlier than the hour-of-day of lastDate, or the same for minute-of-hour - you get a negative value, exactly as you've seen.
Instead, subtract one DateTime from another to get a TimeSpan and use that single TimeSpan for all the components:
DateTime lastDate = DateTime.Parse("2/12/2015 11:24:23 AM");
TimeSpan difference = DateTime.Now - lastDate;
int days = difference.Days;
int hours = difference.Hours;
int minutes = difference.Minutes;
That will still be negative if lastDate is after DateTime.Now, of course.
Note that this will give you a result which is meaningful if you display all three components. For example, it might give you "2 days, 3 hours and 10 minutes". If instead you want to represent the same TimeSpan as "2.194 days" or "51.166 hours" or "3160 minutes" then you can use TotalDays, TotalHours and TotalMinutes.
If you always want a positive TimeSpan - the equivalent of Math.Abs but for TimeSpan you can just use TimeSpan.Duration():
TimeSpan difference = (DateTime.Now - lastDate).Duration();
I was just wondering if there is a way to get the current time and set it into a value.
If its 12:06 AM.. I want to get that time and set it into currentTime.
Example
float currentTime = 0;
currentTime = 12.06;
As others have mentioned, the DateTime class would be ideal for this, and to work out the difference between 2 date/times:
DateTime end = DateTime.Now;
DateTime start = new DateTime(2011, 12, 5, 12, 6,0);
double hours = (end - start).TotalHours;
The subtraction of DateTime objects results in a TimeSpan object that you can use to see the hours/minutes etc.
try DateTime class
DateTime dt = DateTime.Now;
Is this what you're looking for?
DateTime currentTime;
currentTime = DateTime.Now;
Don't use floats or strings. You can do all kinds of cool things using DateTime.
Here's how you'd get the hours that someone worked:
var clockIn = new DateTime(2011,12,4,9,0,0); // December 4th, 9 AM
var clockOut = new DateTime(2011,12,4,17,0,0); // December 4th, 5 PM
var duration = clockOut - clockIn; // TimeSpan
Console.Write(duration.TotalHours); // 8
A few people have mentioned how, but as a 'better' recommendation you should use
DateTime currentTime = DateTime.UtcNow
Otherwise you have issues when the clocks go back, if your timing code is run on those days. (plus it is far easier to alter the UTC time to local time than it is to convert a '1am' to UTC (as there will be two of them when the clocks go back)
Well if you really what it as a float then try:
var currentDate = DateTime.Now;
float currentTime = float.Parse((currentDate.Hour > 12 ? currentDate.Hour -12 :
currentDate.Hour) + "." + currentDate.Minute);
I wouldn't recommend comparing dates or time with floats. A better options would be to use timespans.
You should be using a Timespan instance for time related values, you can use the flexibility to get the required values like
TimeSpan ts = DateTime.Now.TimeOfDay;
ts.ToString("hh:mm") // this could be what you are looking for
You could then use ts.TotalHours which would give you fractional hours (as a double) else you could construct a string specifically using ts.Hours ..ts.Minutes play around and it could be prove useful.
Try the following:
DateTime StartTime=StartTime value;
DateTime CurrentTime=DateTime.Now;
TimeSpan dt = CurrentTime.Subtract(StartTime);
In dt you will get a working time period.
If you want to have the difference between two times, then do this:
DateTime dateOne = DateTime.Parse(enteredTime);
DateTime dateTwo = DateTime.Now;
TimeSpan difference = dateOne - dateTwo;
i am doing a project on cab services.in this rate is different for day and night.
in the form only journey start date and end date is selected.based on this i have to calculate the no of days and nights.
here i am confused how to calculate the no of days and night.
thanks in advance.
private List<DateTime> GetDateRange(DateTime StartingDate, DateTime EndingDate)
{
if (StartingDate > EndingDate)
{
return null;
}
List<DateTime> rv = new List<DateTime>();
DateTime tmpDate = StartingDate;
do
{
rv.Add(tmpDate);
tmpDate = tmpDate.AddDays(1);
} while (tmpDate <= EndingDate);
return rv;
}
To view this code in action, copy and paste the following code into SnippetCompiler:
DateTime StartingDate = DateTime.Parse("02/25/2007");
DateTime EndingDate = DateTime.Parse("03/06/2007");
foreach (DateTime date in GetDateRange(StartingDate,EndingDate))
{
WL(date.ToShortDateString());
}
Sample output :
2/25/2007
2/26/2007
2/27/2007
2/28/2007
3/1/2007
3/2/2007
3/3/2007
3/4/2007
3/5/2007
3/6/2007
Use the Subtract method to get the difference, which is a TimeSpan value. Example:
TimeSpan diff = SecondDate.Subtract(FirstDate);
You can get the length of the time span for example in hours:
double hours = diff.TotalHours;
I'm not sure which time unit "days and nights" could be interpreted as, though. Perhaps days?
double days = diff.TotalDays;
DateTime dt1,dt2;
//...
TimeSpan period = dt1 - dt2;
int days = period.Days;
It sounds like a very long Cab journey that takes days and nights!
I think you need to define what a day and a night is more clearly in order to get your perfect answer. You also need to think about what impact Daylight Saving Time has on your calculations.
If say:
a day was the period from 6am to 6pm
the night was the rest - from 6pm to 6am
and you wanted to really count hours rather than days
In this case then a calculation would require you to:
iterate a currentDateTime from the startDateTime to the endDateTime
choose the increment in the currentDateTime so that it jumps to the next time barrier (6am, 6pm or the endDateTime)
within each loop, then add to your cumulative calculation of numDayHours or numNightHours so far.
Note that:
you could make this calculation quicker by counting whole days along the way
you need to be very careful about the time zone you are calculating in (I just hope that your taxi doesn't cross time zone boundaries!)
you need to be very careful about local time changes - especially "daylight savings time" type changes - the duration from 6pm to 6am is not always 12 hours!
Some pseudo code:
var numDayHours = 0.0;
var numNightHours = 0.0;
var current = startDateTime;
while (current < endDateTime)
{
next_hop = calculate_next_hop (current, endDateTime);
// select next date time
switch (next_hop.hop_type)
{
case HopType.night_time_hop:
numNightHours += next_hop.num_hours;
break;
case HopType.day_time_hop:
numDayHours += next_hop.num_hours;
break;
}
current = next_hop.EndDateTime;
}
// and here is the result
double numDays = numDayHours / 12.0;
double numHours = numNightHours / 12.0;
I have a small problem with the code below, the 'days' variable always seems to be 0 no matter how far apart the days are.
Can you see anything obviously wrong?
System.TimeSpan span = dates[0] - dates[1]; // e.g. 12/04/2010 11:44:08 and 18/05/2010 11:52:19
int days = (int)span.TotalDays;
if (days > 10) //days always seems to be 0
{
throw new Exception("Over 10 days");
}
Thanks
As you are subtracting the later date from the earlier date, according to your comments, TotalDays will be negative. In your example, -36.
Therefore a comparison of (days > 10) will fail. You should use
int days = Math.Abs((int)span.TotalDays);
Assuming you haven't set date[0] equal to date[1], there is no reason why TotalDays will be returning zero for the sample dates you have in your comments.
The total days should be negative but in any case not zero, cause you substract the earlier date from the later date. It seems dates[0] and dates[1] are not containing what you think.
I just tested this:
DateTime date1 = new DateTime(2010, 12, 31);
DateTime date2 = new DateTime(2010, 1, 1);
TimeSpan timeSpan = date2 - date1;
Console.WriteLine(timeSpan.TotalDays);
This program produces the output: -364. So it should perfectly work!
One question: Did you use DateTime[] for the dates-array?
BTW: days > 10 does not check if days is zero.
If we assume your code looks exactly like that, and the dates array is correctly populated, then there is nothing wrong here that would cause days to be exactly zero. Maybe check that your dates array has the correct values in it? Barring that, post more code?
Either do this:
System.TimeSpan span = dates[0] - dates[1];
int days = Math.Abs((int)span.TotalDays);
if (days > 10)
{
throw new Exception("Over 10 days");
}
Or this:
System.TimeSpan span = dates[1] - dates[0];
int days = (int)span.TotalDays;
if (days > 10)
{
throw new Exception("Over 10 days");
}
I'm sure this is very easy, but I've got a sudden mental block.
I'm trying to get a DateTime object for the next occurence of 3am. For example, if DateTime.Now is 16/july/2009 : 12:04pm - the next occurance of 3am would be 17/july/2009 : 03:00
However, if DateTime.Now was 17/july/2009 : 01:00 then the next occurence would still be 17/july/2009 : 03:00 (not the day after).
Does that make sense?
One option:
DateTime now = DateTime.Now;
DateTime today3am = now.Date.AddHours(3);
DateTime next3am = now <= today3am ? today3am : today3am.AddDays(1);
Another:
DateTime now = DateTime.Now;
DateTime today = now.Date;
DateTime next3am = today.AddHours(3).AddDays(now.Hour >= 3 ? 1 : 0)
Lots of ways of skinning that particular cat :)
This is all in local time of course, which means you don't need to worry about time zones. Life becomes trickier if you want to get time zones involved...
Note that it's a good idea to take DateTime.Now once to avoid problems if the date rolls over while you're calculating...
DateTime now = DateTime.Now;
DateTime threeAM = now.Date.AddHours(3);
if (threeAM < now)
threeAM = threeAM.AddDays(1);
//just add 24 - 3 = 21 hours and get Today (start of day) and Add 3 hour
DateTime now = DateTime.Now.AddHours(21).Today.AddHours(3);
An alternative (using a function):
DateTime NextAt(TimeSpan time)
{
DateTime now = DateTime.Now;
DateTime result = now.Date + time;
return (now <= result) ? result : result.AddDays(1);
}
call it like:
DateTime next3am = NextAt(new TimeSpan(3,0,0));
You can do it without an if statement (or conditional operator):
// get the current time
DateTime now = DateTime.Now;
// get a 3:00 AM point in time in the future
DateTime next = now.Date.AddHours(24 + 3);
// subtract the number of whole extra days
next = next.AddDays((now - next).Days);
I always explain that you should get the point in time (DateTime.Now) only once in a calculation like this, as it's a changing value, so do I have to repeat it? Well, I just did. ;)
I think this One:
DateTime.Now.Date.AddHours(3).AddMinutes(0).AddSeconds(0).AddDays(1);