I am trying to develop a simple app for my upskill for c#, however I am stuck and new to the functionality of time with c#,
what I need:
I have a 3 text boxes that will contain start time, end time and time interval.
say user entered 7:00 AM , 12:00 PM , and 60 minutes it will store it inside a datatable and add it inside a listbox.
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 AM
current approach:
I think I need to use the DateTime.AddMinutes(interval) but how am I going to arrive to the logic of it will stop if it reaches the end time? using the DateTime method? I am really confused on what to use, I saw TimeRange, TimeSpan etc.
You can use TimeSpan and DateTime together (to calculate and print respectively)
TimeSpan start = DateTime.Parse("7:00 AM").TimeOfDay;
TimeSpan end = DateTime.Parse("12:00 PM").TimeOfDay;
TimeSpan interval = new TimeSpan(0, 60, 0);
// If Start is bigger than end, Add a day to the end.
if (start > end)
end = end.Add(new TimeSpan(1, 0, 0, 0));
while (true)
{
Console.WriteLine((new DateTime() + start).ToString("hh:mm tt"));
start = start.Add(interval);
if (start > end)
break;
}
Output looks like this,
07:00 AM
08:00 AM
09:00 AM
10:00 AM
11:00 AM
12:00 PM
MS Documentation on TimeSpan
You can use TimeSpan with boolean logical operator to test if the currentTime is less than your endTime.
Below is example code.
TimeSpan startTime;
int interval;
TimeSpan tInterval = new TimeSpan(interval, 0, 0);
TimeSpan endTime;
TimeSpan currentTime = startTime;
while( (currentTime = startTime + tInterval) <= endTime)
{
// add currentTime to list box
}
This should take care of the issue with the End Times being "earlier" than the Start Time:
private static void TestTimeSpan()
{
int minutes = 60;
var interval = new TimeSpan(0,minutes,0);
TimeSpan start = DateTime.Parse("7:00 PM").TimeOfDay;
TimeSpan end = DateTime.Parse("1:00 AM").TimeOfDay;
//End of input data--start of solution
var diffSpan = end - start;
var diffMinutes = diffSpan.TotalMinutes > 0 ? diffSpan.TotalMinutes : diffSpan.TotalMinutes + (60 * 24);
var myTimeList = new List<TimeSpan>();
for(int i = 0; i < diffMinutes + minutes; i += minutes)
{
myTimeList.Add(start);
start = start.Add(interval);
}
myTimeList.ForEach(x => Console.WriteLine((new DateTime() + x).ToString("hh:mm tt")));
}
EDIT
Creating a sequence of Time values based in two input times and an interval is straight forward until the "start time" is earlier than the "end time", because just checking to see if the "end time" is greater than the start time fails your algorithm immediately.
This code utilizes the fact that there are only 24 hours in the day. Since the interval value is given in minutes, we can use that to section those minutes into "steps" of time. This code proceeds to step through each interval in time and capture the time at that step and save that in a List of TimeSpan (the captured value could easily be of type string--formatted as desired).
The trick here is when the "end time" is earlier than the "start time" we get a negative TimeSpan which is then used to calculate the steps to the "end time" on the next day. This is where the (60 * 24) [60 minutes x 24 hrs] part comes in to create the correct "diffMinutes" using a ternary operator.
After that the code simple iterates over the List "myTimeList" to write the formatted TimeSpan to the console. However, this 'List' is just a portable collection that can be sent anywhere in you code to do anything needed.
There are lots of other solutions, this one just seems straightforward, to me.
Related
I'm trying to subtract my potentially negative timespan values from 24 hours to change them into positive values.
As an example case:
I want to find how much time is there till 8:00 AM.
If it's 16:00 PM now, timespan gives me -8 ish value so I want to substract it from 24 to get 16.
I'm trying this but it's giving me this error
The DateTime represented by the string is not supported in calendar
System.Globalization.GregorianCalendar.
What I tried ;
string startTime = String.Format("{0:t}", "8:00");
TimeSpan timeLeft = Convert.ToDateTime(startTime).Subtract(DateTime.Now);
if (timeLeft.TotalMinutes < 0 )
{
timeLeft = Convert.ToDateTime(String.Format("{0:H}","24:00")).Subtract(Convert.ToDateTime(timeLeft.Negate())) ;
}
How can I achieve subtracting my potentially negative timespans from 24 hours?
You are confusing TimeSpan and DateTime. I guess there is an easier way:
var eightOClock = TimeSpan.FromHours(8);
var now = DateTime.Now;
var till8again = now.TimeOfDay > eightOClock
? TimeSpan.FromHours(32) - now.TimeOfDay
: eightOClock - now.TimeOfDay;
So if TimeOfDay is less than eight hours (it's before 8am), we take the difference to 8am. If it's greater than 8am, we take the difference to 32hours, which is 8am tomorrow.
A DateTime is an absolute date, happening at a certain day, month, year... It must not be used to represent a specific hour.
So your attempt to convert "8:00", or "24:00" in a DateTime will forcibly fail.
For this you must use TimeSpan (or eventually an integer if you always work with hours).
You can use for example
if(DateTime.Now.TimeOfDay > TimeSpan.FromHours(8))
To see if it's more or less than 8:00.
TimeOfDay will return you the amount of time elapsed for today since midnight.
DateTime has also a lot of useful methods to Add or Substract time, see https://msdn.microsoft.com/fr-fr/library/system.datetime(v=vs.110).aspx for details
Use TimeSpan, and if the startDate is less the Now, add a day to it and then make the comparison.
TimeSpan startTime = new TimeSpan(8,0,0);
TimeSpan now = DateTime.Now.TimeOfDay;
startTime = startTime < now ? startTime.Add(TimeSpan.FromDays(1)) : startTime;
TimeSpan diff = startTime - now;
Another point: the error is coming from the fact that 24:00 doesn't represent 12:00 midnight. 0:00 represents midnight, and that will be a valid DateTime.
Let's say that I have this DateTime(Mar/01/2015 09:55:52)
I want to know if that time (I think this time is from Germany, anyways, I'm living in Brazil and the difference between us is 4hours).
So basically:
DateTime I have: Mar/01/2015 09:55:52
DateTime.Now That representes "where I am": Mar/01/2015 05:55:52
I want to make this parse to tell me, for example, if that "DateTime that I have" is 1 minutes after at least and 10 minuts later at maximum from the "DateTime where I am".
If you are on .net 4.5 - you can use the TimeZoneInfo class, it has a ConvertTime method that lets you pass in a datetime and a timezone
TimeZoneInfo.ConvertTime Method (DateTime, TimeZoneInfo)
you can use it like:
DateTime dateTimeIhave = TimeZoneInfo.ConvertTime(dateTheyGave, theirTimeZone, yourTimeZone);
if (dateTimeIhave > DateTime.Now.AddMinutes(1)
&& dateTimeIhave < DateTime.Now.AddMinutes(10))
{
doSomething();
}
//pseudocode
//DateTime that represents where you're at = dnow;
//DateTime that you have = dhave;
//convert dnow and dhave to seconds using this algorithm:
//convert the time into a string and get the data using a parser.
//int seconds = current seconds;
//seconds += minutes * 60;
//seconds += hours * 60 * 60;
Then find out if both times are between 60 seconds and 600 seconds from each other.
I am creating a function that will set the date of an event, based on the current time.
I have an enumeration of events:
public enum EventTimings
{
Every12Hours, // 12pm and midnight
Weekly // sunday at midnight
}
public static DateTime CalculateEventTime(EventTimings eventTime)
{
DateTime time;
switch(eventTime)
{
case EventTimings.Every12Hours:
break;
}
return time;
}
So (Every12Hour event type) if the current time is 10am, then the eventdate will be the same day but at 12pm.
How should I write this?
I also have to make sure this works for December 31st and any other strange outlier date/time.
Is datetime the best for this scenerio?
If you want to be able to test anything, I would make the DateTime you are trying to "round" explicit, something like
public static DateTime RoundedDate(DateTime eventTime, EventTimings strategy)
{
switch (strategy)
case EventTimings.Weekly :
return WeeklyRounding(eventTime);
... etc ...
That way you can now write a specialized method for the 12-hour interval, the week interval, and test it for any input date possible, without depending on your computer clock.
You could also try something like this, although it breaks down if you want to do something monthly (because months each have a different number of days.) Also, while this simplified method will ensure a returned date at 12 and midnight, the weekly offset would be every 7 days from the starting day... not necessarily on Sundays. You could easily accomodate that behavior with a switch statement, though. The overloaded method also allows you some flexibility to provide a custom offset.
Also, to answer your question, yes I would use System.DateTime and System.TimeSpan. They handle determining whether a year or month has "rolled over" for you.
public enum EventTimings : int
{
Default = 12, // Default every 12 hours.
NoonAndMidnight = 12, // Every 12 hours.
Weekly = 168, // 168 hours in a week.
ThirtyDays = 720 // 720 hours in 30 days.
}
public DateTime CalculateDateTime(DateTime starting, EventTimings timing)
{
return CalculateDateTime(starting, TimeSpan.FromHours((int)timing));
}
public DateTime CalculateDateTime(DateTime starting, TimeSpan span)
{
DateTime baseTime = new DateTime(starting.Year, starting.Month, starting.Day, starting.Hour >= 12 ? 12 : 0, 0, 0);
return baseTime.Add(span);
}
I agree to keep it generic by making the reference date an input parameter instead of current datetime. However as you have asked about the logic for your eventTime values as well, this is how I would go about.
How should I write this?
For every12hours, check the hour property of the input date and check if it is less than 12. If so, then create a new TimeSpan for 12pm and add it to the datepart of the input date.
If not, add 1 day to the input date, create a TimeSpan for 12am and add it to the datepart of inputdate.
For weekly (Monday 12am), check the dayoftheweek of the inputdate and just add number of days to make it equal to the incoming Monday (Which is as simple as (8 - dayoftheweek)) and add a 12am TimeSpan to the date of the incoming Monday's date.
public enum EventTimings
{
Every12Hours, // 12pm and midnight
Weekly // sunday at midnight
}
public static DateTime CalculateEventTime(EventTimings eventTime, DateTime inputDate)
{
DateTime time = DateTime.Now;
switch (eventTime)
{
case EventTimings.Every12Hours:
time = inputDate.Hour > 12 ? inputDate.AddDays(1).Date + new TimeSpan(0, 0, 0) : inputDate.Date + new TimeSpan(12, 0, 0);
return time;
case EventTimings.Weekly:
int dayoftheweek = (int) inputDate.DayOfWeek;
time = inputDate.AddDays(8 - dayoftheweek).Date + new TimeSpan(0, 0, 0);
return time;
// other cases
}
}
Is datetime the best for this scenerio?
Yes. Your datetime calculations using DateTime and TimeSpan should take care of leap years, daylight savings or endofyear scenarios. Additionally you could try adding SpecifyKind to denote it is local time.
The algorithm I'd follow goes like this...
Put noon on the day of eventTime into a variable
Check if that variable is before eventTime
If it's not, add 12 hours to it
Return the variable
switch (strategy)
{
case EventTimings.Every12Hours:
//get noon for the event date
DateTime x = eventTime.Date.AddHours(12);
//check to see if x is after the eventTime
if (x < eventTime)
{
//if so, advance x by 12 hours to get midnight on the next day
x = x.AddHours(12);
}
return x;
break;
//other cases...
}
I have a DateTime object that is 10:00 AM
This time represents what time of day a report should be run.
I want to calculate the amount of time remaining from NOW until 10:00 AM
part of my confusion is NOW might be after 10:am or BEFORE 10am,
I keep playing around with TimeSpan, but my results are not quite right... I am sure this is simple, but it is one of those things I have been working of for a few hours and I need a push in the right direction...
I want the timespan object timeTillRun to be correct...here is what I have tried:
{
DateTime scheduledRun = DateTime.Today.AddHours(_timeToStart);//_timeToStart = 10
TimeSpan timeTillRun = DateTime.Now - scheduledRun;
}
This will work... but you need to reverse the order of subtraction:
TimeSpan timeTillRun = scheduledRun - DateTime.Now;
Note that if it's currently after 10AM, timeTillRun will be negative. You will presumably also need to check if the current time is on or after 10AM, then add 10 hours and one day to DateTime.Today to obtain the next run time. Alternatively, you could test if timeTillRun is negative; if so, just add one day to it (timeTillRun += new TimeSpan(1, 0, 0, 0)).
Try this
DateTime timeToStart = DateTime.Today.AddHours(10);
TimeSpan timeTillRun;
// Checking to see if current time is passed schedule run, if it is then we add a day (this is assuming this is run daily, if days are skipped like weekends for example then this would need some tweaking)
if (DateTime.Now > timeToStart)
timeTillRun = DateTime.Now.AddDays(1.0) - timeToStart;
else
timeTillRun = DateTime.Today - timeToStart;
double totalHoursRemaining = timeTillRun.TotalHours; // get total hours remaining
string prettyRemaining = String.Format("{0} day and {1} hours", timeTillRun.Days, timeTillRun.Hours); // can do some outputting here
I have a service that user can configure to run during "off-peak" hours. They have the ability to set the time frame that the service can run.
For Example:
User A works 8am-5pm, so they want to schedule the app to run between 5:30pm and 7:30am.
User B works 9pm-6am, so they schedule the app to run between 6:30am and 8:30 pm.
The point is that the app uses their computer while they are not.
Given a DateTime of the current time, a DateTime of the start and a DateTime of the stop time, how can I check if current is between start and stop.
The tricky part for me is that the time can cross the midnight boundary.
If startTime and endTime represent a single time interval (it will only happen once, and startTime and endTime represent the date and the time to start/stop), then it's as easy as saying
bool isTimeBetween = someTime >= startTime && someTime <= endTime;
If it's a recurring event (happens every day, during some interval), you can do comparisons using the TimeOfDay property. (The recurring case is the one where you have to consider a start/stop that crosses midnight)
static public bool IsTimeOfDayBetween(DateTime time,
TimeSpan startTime, TimeSpan endTime)
{
if (endTime == startTime)
{
return true;
}
else if (endTime < startTime)
{
return time.TimeOfDay <= endTime ||
time.TimeOfDay >= startTime;
}
else
{
return time.TimeOfDay >= startTime &&
time.TimeOfDay <= endTime;
}
}
(Note: This code assumes that if start == end, then it covers all times. You made a comment to this effect on another post)
For example, to check if it's between 5 AM and 9:30 PM
IsTimeOfDayBetween(someTime, new TimeSpan(5, 0, 0), new TimeSpan(21, 30, 0))
If startTime and endTime are DateTimes, you could say
IsTimeOfDayBetween(someTime, startTime.TimeOfDay, endTime.TimeOfDay)
So I assume from the question that you want to know if given a start time and end time for a day (not including the actual date, i.e., 1/1/1900 or something like that) to see if another time is with the time specified by start and end. E.g., if start is 9pm and end is 9am, accept 10pm but reject 10am.
You can do this either per time range types (times are equal, end is after start, end is before start) which is simple:
if (end==start) return true
else if (end>start) return start<=time && time<=end
else return !(time>end && time<start)
Or you can extend the range of start and end such that end is always after start as such:
if (end<=start) end += <24 hours>
if (time<start) time+= <24 hours>
return time<=end
I'm assuming you are saving the start and end times in the applications configuration file, so all you basically have to do is have your application set a flag to "on" when the "start time" occurs and set it to "off" when the stop time occurs.
That way you don't have to be constantly checking if "now" is "between start and end" times.
DateTime t1;
t1 = DateTime.Now;
// loop inbetween start and end time
if (t1>=start_time &&t1<=end_time)
{
//your code / action
}
//if you are using sql to get values
start_time = Convert.ToDateTime(row.Cells[10].Text);
end_time = Convert.ToDateTime(row.Cells[11].Text);
//convert them to string or you will get some error!!!