Is there a nice concise way to write this logic in C#?
if ((DateTime.Now >= "8:00 AM") && (DateTime.Now < 5:00 PM))
{// do something}
I am making a demo app where I want to make something happen in the work day, but I don't want this code to stand out much (a lot of casting = bad). (Because I want my demo stuff to be easier to see.
Well, you could do:
DateTime now = DateTime.Now;
if (now.Hour < 8 || now.Hour >= 17)
Note that I generally prefer to only use the DateTime.Now property once, copying the result into the local variable as above - that way you don't get odd possibilities due to the time changing between calls. Not a problem here, but it could be in other cases.
Another possibility is to use DateTime.TimeOfDay if you want to handle things that way. I think the above is about as simple as it gets though.
EDIT: Steven pointed out that I changed the && in your original logic to || - your original logic can never work, as it can never be before 8am and after 5pm. The above works for "if it's not in the working day" - if you want "if it is in the working day" you just need:
DateTime now = DateTime.Now;
if (now.Hour >= 8 && now.Hour < 17)
I think what you want to do here is something like this:
var now = DateTime.Now;
if (now.Hour >= 8 && now.Hour < 17)
If you wanted to make it "pretty" you could also use an extension method:
public static class DateTimeHelper
{
public static DateTime Time(this string time)
{
DateTime theTime = DateTime.Parse(time);
return theTime;
}
}
...
if (DateTime.Now < "8:00 AM".Time() && DateTime.Now > "5:00 PM".Time())
{
// do something
}
If you can format a string in the right format for the current date and start / end times you can use something like this.
DateTime now = DateTime.Now;
DateTime start = Convert.ToDateTime(now.Date.ToShortDateString() + " 8:00:00 AM");
DateTime end = Convert.ToDateTime(now.Date.ToShortDateString() + " 5:00:00 PM");
if (now >= start && now < end)
{
}
I still think it's cleaner to use the hour method posted by others, but this is a method that provides an answer similar to how you asked your question.
Related
I have the following code, and I am planning to use it to check if the user has placed a correct number of days between two datetimepickers.
I've searched on google, and some posts say use var, some say parse, and still it wont work, the message box won't pop up upon checking.
I have already made it work by using a label as a container of the result and use an if else statement to check if the text is equal to 14,15 or 16. It works cause i only need to detect if its 14, 15 or 16, but what if i was given a situation where i need to compare large numbers, I wish I a better solution than what i have right now.
Can someone please tell me how to compare time spans in an if else statement properly? Thank you so much. have a nice day :)
DateTime dateFrom = from_dtPicker.Value;
DateTime dateTo = to_dtPicker.Value;
TimeSpan DayDifference = dateTo - dateFrom;
double NumberOfDays = DayDifference.TotalDays;
if ((NumberOfDays < 14) && (NumberOfDays > 16))
{
//message box
}
Here's what i mean with my weird solution though,
DateTime dateFrom = pp_from_dtPicker.Value;
DateTime dateTo = pp_to_dtPicker.Value;
TimeSpan DayDifference = dateTo - dateFrom;
numofdaysLBL.Text = DayDifference.TotalDays.ToString();
if ((numofdaysLBL.Text != "14") && (numofdaysLBL.Text != "15") && (numofdaysLBL.Text != "16"))
{
//msgbox
}
It seems to me, that your comparison is the problem here
if ((NumberOfDays < 14) && (NumberOfDays > 16))
NumberOfDays can never be less than 14 AND more than 16 at the same time. Instead invert the comparison:
if ((NumberOfDays >= 14) && (NumberOfDays <= 16))
EDIT: Maybe I misunderstood what you are asking (as pointed out in the comments). If you want a more generic solution for comparing dates, you can simply wrap your code into a function
bool AreDatesClose(DateTime d1, DateTime d2, double minDaysApart, double maxDaysApart)
{
var timespan = d1 - d2;
return timespan.TotalDays >= minDaysApart && timespan.TotalDays <= maxDaysApart;
}
You can write a function which will give you that NumberOfDays is in between given range or not
public bool IsGivenDateInRange(double numberOfDays, double startDate, double endDate)
{
return numberOfDays >= startDate && numberOfDays <= endDate;
}
Now use this function in if condition
if(IsGivenDateInRange(NumberOfDays, 14, 16)) //Instead of 14 and 16 you can use any number
{
//Your logic
}
As per new edit in your question if you want to show message box when date does not come in these range, then you can use same function but with negation
if(!IsGivenDateInRange(NumberOfDays, 14, 16)) //Instead of 14 and 16 you can use any number
{
//MessageBox.Show();
//Your logic
}
I have been trying to use an ajax CalenderExtender for my application.
I have many small operations in my app like adding duration to start date of a task to find the finish date, change duration of a task if its end date is changed (depending on its start date),etc.
But while I do all these operations I want to skip all the holidays and saturday , sundays from the calculations for eg. a task starting on 01/23/2014 with a duration of 5 days should finish on 01/29/2014 (adding 2 days for sat n sun in duration) instead of 01/27/2014. Same should be performed on other operations as well.
Is there a way to do this?
For Sundays and Saturdays, it's easy. Just check the DateTime.DayOfWeek property of your dates.
If you have an operation that will start on date start and will end on date end, you can see what dates are Saturdays or Sundays like this:
List<DateTime> satsAndSundays;
for (DateTime temp = start; temp <= end; temp.AddDays(1))
{
if (temp.DayOfWeek == DayOfWeek.Sunday ||
temp.DayOfWeek == DayOfWeek.Saturday)
{
satsAndSundays.add(temp);
}
}
And since you can know how many days there are between start and end by doing something like:
TimeSpan span = end - start;
int totalDays = (int)span.TotalDays;
// TotalDays is actually a double, I'm just discarding the non integer part.
You may fid out how many work days you have there by doing totalDays - satsAndSundays.Count.
Edit: I just read the question again. If you want a task to start on a given date, and take x work days, you can do it like this:
DateTime end = start;
for (int i = x; i >= 0;) // the third parameter of the for is empty on purpose
{
end = end.AddDays(1);
if (end.DayOfWeek != DayOfWeek.Saturday &&
end.DayOfWeek != DayOfWeek.Sunday)
{
i--;
}
}
Afther the loop, end will be x workdays after start (provided there are no holidays in between).
For holidays, though, there is no alghoritm for that in the framework. You need to fetch them from some source (a file, a database, a web service etc.). Or you could write your own program to figure them out - most holidays that are not on a fixed date do follow formulas when it comes to when they happen. Do take into account, however, that holidays may vary by culture and region. If your application is to be used throughout a country, for example, it may be quite the effort to implement city-wide holidays. Depending on your needs, it might even be better to either let the users input which days are holidays, or making your own database your app can access and use.
Try this one..
private string GetDatesOfSundays(DateTime DatMonth)
{
string sReturn = "";
int iDayOffset = DatMonth.Day - 1;
DatMonth = DatMonth.AddDays(System.Convert.ToDouble(-DatMonth.Day + 1));
DateTime DatMonth2 = DatMonth.AddMonths(1).AddDays(System.Convert.ToDouble(-1));
while (DatMonth < DatMonth2)
{
if (DatMonth.DayOfWeek == System.DayOfWeek.Sunday)
{
if (sReturn.Length > 0) sReturn += ",";
sReturn += DatMonth.ToShortDateString();
}
DatMonth = DatMonth.AddDays(1.0);
}
return sReturn;
}
I have a DateTime object that I'd like to check and see if it falls within the last 24 hours.
I did something like this but its wrong:
myDateTime > DateTime.Now.AddHours(-24) && myDateTime < DateTime.Now
where did I go wrong?
There is nothing wrong with the code that you posted, so whatever you did wrong is somewhere else in the code.
I only see two minor flaws in the code, but they only affect corner cases:
You should avoid getting the DateTime.Now property repeatedly in the code. Its value changes, so you may get inconsistent results in some cases when the values changes from one use to the next.
To get a time interval you would usually pair one inclusive and one exclusive operator, like > and <=, or >= and <. That way you can check for intervals next to each other, like 0 - 24 hours and 24 - 28 hours, without getting a gap or an overlap.
DateTime now = DateTime.Now;
if (myDateTime > now.AddHours(-24) && myDateTime <= now)
Only get DateTime.Now once within the function - otherwise the value might change.
Use <=, not <. if you check a microsecond after the time has been set, it will still be equal to DateTime.Now. I actually ran into this in production code where imports wouldn't show up in a different query that checked < because the import was too fast!
Use this code:
DateTime now = DateTime.Now;
DateTime yesterday = now.AddDays(-1);
if (myDateTime > yesterday && myDateTime <= now) {
...
}
Learning from both the above answers and also to improve the readability of the code we can use a method like this.
using System;
public class Program
{
public static void Main()
{
DateTime myDateTime = DateTime.Parse("2021-08-25T20:20:19.5540211");
DateTime now = DateTime.Now;
DateTime yesterday = now.AddHours(-24);
if (IsBewteenTwoDates(myDateTime, yesterday, now))
{
Console.WriteLine("this date ({0}) is between {1} & {2}", myDateTime, yesterday, now);
}
else
{
Console.WriteLine("this date ({0}) is not between {1} & {2}", myDateTime, yesterday, now);
}
}
// Checks if the DateTime object dt is between start and end DateTime.
public static bool IsBewteenTwoDates(DateTime dt, DateTime start, DateTime end)
{
return dt >= start && dt <= end;
}
}
Check the fiddle here.
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);
DateTime dt=Convert.ToDateTime(data);
if ((dt.Year == DateTime.Now.Year)
&& (dt.Month == DateTime.Now.Month)
&& (dt.Day == DateTime.Now.Day))
lblDate.Text = "Today";
This code too lazy
How to compare 2 date variables the easy way?
How to get the difference of 2 date variables in minutes?
For the first question:
In general:
if (first.Date == second.Date)
To check whether a DateTime is "today"
if (dateTime.Date == DateTime.Today)
Note that this doesn't take any time zone issues into consideration... What do you want to happen if the other DateTime is in UTC, for example?
I'm not sure what you mean by the second question. Could you elaborate? You can do:
TimeSpan difference = first - second;
if that's any help... look at the TimeSpan documentation for more information about what's available. For instance, you may mean:
double minutes = (first - second).TotalMinutes;
but you may not...
1. DateTime.Equals(DateTime dt1, DateTime dt2)
DateTime dt=Convert.ToDateTime(data);
if (dt.Date == DateTime.Today)
lblDate.Text = "Today";
you can use subtract Method
DateTime dt=Convert.ToDateTime(data);
id(dt==DateTime.Now)
{
lblDate.Text = "Today";
}
1. if (dt.Date == DateTime.Today)
2. (first - second).TotalMinutes