Develop Reference

Easily calculate the time before midnight in C#

I have a function which is already compact, i wanted to know if there was better (like a DateTime functionality already included).
Currently i use this:
DateTime today = DateTime.Now;
DateTime tomorrow = new DateTime(today.Year, today.Month, today.Day, 0, 0, 0).AddDays(1);
double remaining = (tomorrow - today).TotalMilliseconds;
Thank for reading.

You can simplify the tomorrow value by just doing this and taking the benefit of DateTime.Today:
DateTime tomorrow = DateTime.Today.AddDays(1);
So your code will be easy to read:
DateTime today = DateTime.Now;
DateTime tomorrow = DateTime.Today.AddDays(1);
double remaining = (tomorrow - today).TotalMilliseconds;

You can create extension for DateTime
public static class DateExtensions
{
public static double GetNextDayRemainingMs(this DateTime dateTime)
{
return (dateTime.AddDays(1).Date - dateTime).TotalMilliseconds;
}
}
Usage
DateTime.Now.GetNextDayRemainingMs();

You can try following code
(DateTime.Today.AddDays(1)-DateTime.Now).TotalMilliseconds

Instead of defining instance for tomorrow variable you can use .AddDate(1).Date property
.AddDate(1) will add one day to DateTime.Now and .Date property
will give you only date and sets time to 00.
DateTime today = DateTime.Now;
double remaining = (today.AddDate(1).Date - today).TotalMilliseconds;
Or (Elegant way)
You can use Today property of DateTime.
An object that is set to today's date, with the time component set to
00:00:00.
double remaining = (DateTime.Today.AddDays(1)-DateTime.Now).TotalMilliseconds

Change the time forward

I am getting dates from the database and for each date I want to change the time forward starting from the DateTime that was obtained from the database until I get to a given Fixed Time (Y). However, (Y) might be in the next day.
For example if the date from the database is [7/6/2017 5:00:00 AM] and the given Fixed Time is 10:00 PM then I want to get [7/6/2017 10:00:00 PM].
However if the fixed time is 02:00 AM then I want to get [7/7/2017 02:00:00 AM] (notice that the date has increased by one)
Note: The code is running, but I modified the code to make it shorter and make more sense. Thus, there might be syntax or spelling mistakes.
My first solution was something like this:
private DateTime setTimeForeward(DateTime date) {
DateTime today = DateTime.ParseExact(FixedTime, "hh:mm tt", CultureInfo.InvariantCulture);
TimeSpan difference = today.TimeOfDay - date.TimeOfDay;
return date + difference;
}
That didn't work as expected when the fixed time is 02:00 AM. The difference becomes negative( it doesn't go around the clock) and the date will be [7/6/2017 02:00:00 AM].
I ended up with the following code
private DateTime setTimeForeward(DateTime date) {
DateTime today = DateTime.ParseExact(FixedTime "hh:mm tt", CultureInfo.InvariantCulture);
TimeSpan difference = today.TimeOfDay - date.TimeOfDay;
if (difference.Hours < 0) {
difference += new TimeSpan(24, 0, 0);
}
return date + difference;
}
I am not sure if my function is logically correct and I feel like I am overthinking it. Also,I am not sure if there's a better way or a built in function that does what I want for me. Basically, I am looking for a correct and an elegant solution.
Thank you very much in advanced.

In this method, I'm using DateTime fixedTime to represent a time. I don't really care about it's Day, Month, and Year values.
static DateTime GetClosingTime(DateTime fixedTime, DateTime dbTime)
{
var cutoff = new DateTime(dbTime.Year, dbTime.Month, dbTime.Day, fixedTime.Hour, fixedTime.Minute, fixedTime.Second);
if (dbTime < cutoff)
return cutoff;
else
{
cutoff = cutoff.AddDays(1);
return cutoff;
}
}
Here's calling it with your provided example input.
var FixedTime10PM = new DateTime(1, 1, 1, 22, 0, 0);
var FixedTime02AM = new DateTime(1, 1, 1, 2, 0, 0);
var dbTime = new DateTime(2018, 6, 20, 5, 0, 0);
var dt1 = GetClosingTime(FixedTime10PM, dbTime);
var dt2 = GetClosingTime(FixedTime02AM, dbTime);
Console.WriteLine(dt1.ToLongDateString() + " " + dt1.ToLongTimeString());
Console.WriteLine(dt2.ToLongDateString() + " " + dt2.ToLongTimeString());
And here's my output:
EDIT:
Simplified method based on suggestions in comments:
static DateTime GetClosingTime(DateTime fixedTime, DateTime dbTime)
{
var cutoff = new DateTime(dbTime.Year, dbTime.Month, dbTime.Day, fixedTime.Hour, fixedTime.Minute, fixedTime.Second);
return dbTime < cutoff ? cutoff : cutoff.AddDays(1);
}

Your logic is almost right but you shouldn't be checking for difference.Hours because there might be a difference in minutes (or even seconds if you changed the format later).
I adjusted your function and changed some variable names to make them easier to follow:
private DateTime SetTimeForward(DateTime originalDate)
{
TimeSpan newTime = DateTime.ParseExact(FixedTime,
"hh:mm tt",
CultureInfo.InvariantCulture).TimeOfDay;
TimeSpan diff = newTime - originalDate.TimeOfDay;
if (diff.Ticks < 0)
diff = diff.Add(new TimeSpan(24, 0, 0));
return originalDate.Add(diff);
}
Some remarks:
If your FixedTime is really fixed, you might want to store it directly as a TimeSpan so you don't have to parse it every time.
If you parse the FixedTime because it's changeable, you might pass it as a second argument instead:
private DateTime SetTimeForward(DateTime originalDate, string fixedTime)
Or:
private DateTime SetTimeForward(DateTime originalDate, TimeSpan newTime)
The current implementation does not change the date value if the newTime is equal to originalDate.TimeOfDay. I.E., If the originalDate is 7/6/2017 2:00 AM and the FixedTime/newTime is 02:00 AM, the returned date will be equal to the originalDate. If that's not your desired behavior, you might change diff.Ticks < 0 to diff.Ticks <= 0.

Slightly different approach:
private DateTime setTimeForeward(DateTime date)
{
var targetTimeOfDay = TimeSpan.ParseExact(FixedTime, "hh:mm tt", CultureInfo.InvariantCulture);
if (targetTimeOfDay < date.TimeOfDay)
{
date = date.AddDays(1);
}
return date.Date + targetTimeOfDay;
}
I'm getting target time as TimeSpan from the beginning instead of creating DateTime and getting TimeOfDay (which is TimeSpan).
Then I check if the target time of day is lower than time to be modified and if it is I add one day.
I use date.Date + targetTimeOfDay as return value as date.Date will return date with time set to 00:00 and adding target time to it will already set the target hour without calculating the difference.

Converting multiple integer values to a DateTime

I have some int values such as hour and minute. I would like to use these values to create a DateTime format so I can check whether the current time of the computer is after a predefined time.
Any help on this would be highly appreciated as I have looked and found nothing so far.

Have you tried one of the DateTime constructors:
public DateTime(
int year,
int month,
int day,
int hour,
int minute,
int second
)
So you can do something like:
var h = 12;
var m = 34;
var s = 10;
var example = new DateTime(2016,6,22,h,m,s);

Just for completeness' sake, you can add the time part to DateTime.Today :
DateTime.Today.Add(new TimeSpan(hours,minutes,seconds));
This makes the intention of the code clearer:
var target=DateTime.Today.Add(new TimeSpan(hours,minutes,seconds));
if (target>DateTime.Now) ...

create a date time object , with only hours, minute, second field using your custom values
var myDate= new DateTime (DateTime.Today.Year, DateTime.Today.Month, DateTime.Today.Day, hours, minute, second);

DateTime dt = DateTime.ParseExact(timeAsInt, "HHmm", CultureInfo.InvariantCulture);

Convert time span value to format "hh:mm Am/Pm" using C#

I have a value stored in variable of type System.TimeSpan as follows.
System.TimeSpan storedTime = 03:00:00;
Can I re-store it in another variable of type String as follows?
String displayValue = "03:00 AM";
And if storedTime variable has the value of
storedTime = 16:00:00;
then it should be converted to:
String displayValue = "04:00 PM";

You can do this by adding your timespan to the date.
TimeSpan timespan = new TimeSpan(03,00,00);
DateTime time = DateTime.Today.Add(timespan);
string displayTime = time.ToString("hh:mm tt"); // It will give "03:00 AM"

Very simple by using the string format
on .ToSTring("") :
if you use "hh" ->> The hour, using a 12-hour clock from 01 to 12.
if you use "HH" ->> The hour, using a 24-hour clock from 00 to 23.
if you add "tt" ->> The Am/Pm designator.
exemple converting from 23:12 to 11:12 Pm :
DateTime d = new DateTime(1, 1, 1, 23, 12, 0);
var res = d.ToString("hh:mm tt"); // this show 11:12 Pm
var res2 = d.ToString("HH:mm"); // this show 23:12
Console.WriteLine(res);
Console.WriteLine(res2);
Console.Read();
wait a second, there is a catch, the system Culture !!, the same code executed on windows set to different language
especially with different culture language will generate different result.
for example in windows set to Arabic language the result Will be like this :
// 23:12 م
م means Evening (first letter of مساء) .
in windows set to German language i think it will show // 23:12 du.
you can change between different format on windows control panel under windows regional and language -> current format (combobox) and change... apply it, do a rebuild (execute) of your app and watch what i'm talking about.
so how can you force showing Am and Pm prefix in English event if the culture of the current system isn't set to English ?
easy just by adding two lines ->
the first step add using System.Globalization; on top of your code
and modify the previous code to be like this :
DateTime d = new DateTime(1, 1, 1, 23, 12, 0);
var res = d.ToString("HH:mm tt", CultureInfo.InvariantCulture); // this show 11:12 Pm
InvariantCulture => using default English Format.
another question I want to have the pm to be in Arabic or specific language, even if I use windows set to English (or other language) regional format?
Solution for Arabic Exemple :
DateTime d = new DateTime(1, 1, 1, 23, 12, 0);
var res = d.ToString("HH:mm tt", CultureInfo.CreateSpecificCulture("ar-AE"));
this will show // 23:12 م
event if my system is set to English region format.
you can change "ar-AE" if you want to another language format. there is a list for each language.
exemples :
ar ar-SA Arabic
ar-BH ar-BH Arabic (Bahrain)
ar-DZ ar-DZ Arabic (Algeria)
ar-EG ar-EG Arabic (Egypt)
.....

You can add the TimeSpan to a DateTime, for example:
TimeSpan span = TimeSpan.FromHours(16);
DateTime time = DateTime.Today + span;
String result = time.ToString("hh:mm tt");
Demo: http://ideone.com/veJ6tT
04:00 PM
Standard Date and Time Format Strings

Doing some piggybacking off existing answers here:
public static string ToShortTimeSafe(this TimeSpan timeSpan)
{
return new DateTime().Add(timeSpan).ToShortTimeString();
}
public static string ToShortTimeSafe(this TimeSpan? timeSpan)
{
return timeSpan == null ? string.Empty : timeSpan.Value.ToShortTimeSafe();
}

string displayValue="03:00 AM";
This is a point in time , not a duration (TimeSpan).
So something is wrong with your basic design or assumptions.
If you do want to use it, you'll have to convert it to a DateTime (point in time) first. You can format a DateTime without the date part, that would be your desired string.
TimeSpan t1 = ...;
DateTime d1 = DateTime.Today + t1; // any date will do
string result = d1.ToString("hh:mm:ss tt");
storeTime variable can have value like
storeTime=16:00:00;
No, it can have a value of 4 o'clock but the representation is binary, a TimeSpan cannot record the difference between 16:00 and 4 pm.

You will need to get a DateTime object from your TimeSpan and then you can format it easily.
One possible solution is adding the timespan to any date with zero time value.
var timespan = new TimeSpan(3, 0, 0);
var output = new DateTime().Add(timespan).ToString("hh:mm tt");
The output value will be "03:00 AM" (for english locale).

You cannot add AM / PM to a TimeSpan. You'll anyway have to associate the TimaSpan value with DateTime if you want to display the time in 12-hour clock format.
TimeSpan is not intended to use with a 12-hour clock format, because we are talking about a time interval here.
As it says in the documentation;
A TimeSpan object represents a time interval (duration of time or elapsed time) that is measured as a positive or negative number of days, hours, minutes, seconds, and fractions of a second. The TimeSpan structure can also be used to represent the time of day, but only if the time is unrelated to a particular date. Otherwise, the DateTime or DateTimeOffset structure should be used instead.
Also Microsoft Docs describes as follows;
A TimeSpan value can be represented as [-]d.hh:mm:ss.ff, where the optional minus sign indicates a negative time interval, the d component is days, hh is hours as measured on a 24-hour clock, mm is minutes, ss is seconds, and ff is fractions of a second.
So in this case, you can display using AM/PM as follows.
TimeSpan storedTime = new TimeSpan(03,00,00);
string displayValue = new DateTime().Add(storedTime).ToString("hh:mm tt");
Side note :
Also should note that the TimeOfDay property of DateTime is a TimeSpan, where it represents
a time interval that represents the fraction of the day that has elapsed since midnight.

To avoid timespan format limitations, convert to datetime.
Simplest expression would be:
// Where value is a TimeSpan...
(new DateTime() + value).ToString("hh:mm tt");

Parse timespan to DateTime and then use Format ("hh:mm:tt"). For example.
TimeSpan ts = new TimeSpan(16, 00, 00);
DateTime dtTemp = DateTime.ParseExact(ts.ToString(), "HH:mm:ss", CultureInfo.InvariantCulture);
string str = dtTemp.ToString("hh:mm tt");
str will be:
str = "04:00 PM"

You can try this:
string timeexample= string.Format("{0:hh:mm:ss tt}", DateTime.Now);
you can remove hh or mm or ss or tt according your need
where
hh is hour in 12 hr formate,
mm is minutes,ss is seconds,and tt is AM/PM.

Parse timespan to DateTime. For Example.
//The time will be "8.30 AM" or "10.00 PM" or any time like this format.
public TimeSpan GetTimeSpanValue(string displayValue)
{
DateTime dateTime = DateTime.Now;
if (displayValue.StartsWith("10") || displayValue.StartsWith("11") || displayValue.StartsWith("12"))
dateTime = DateTime.ParseExact(displayValue, "hh:mm tt", CultureInfo.InvariantCulture);
else
dateTime = DateTime.ParseExact(displayValue, "h:mm tt", CultureInfo.InvariantCulture);
return dateTime.TimeOfDay;
}

At first, you need to convert time span to DateTime structure:
var dt = new DateTime(2000, 12, 1, timeSpan.Hours, timeSpan.Minutes, timeSpan.Seconds)
Then you need to convert the value to string with Short Time format
var result = dt.ToString("t"); // Convert to string using Short Time format

Because this situation is as annoying as it is common... I created a helper class, which I have released in a NuGet package. This could be a private method and can be used in MVC views as well as in back-end C# code.
public static string AsTimeOfDay(TimeSpan timeSpan, TimeSpanFormat timeSpanFormat = TimeSpanFormat.AmPm)
{
int hours = timeSpan.Hours;
int minutes = timeSpan.Minutes;
string AmOrPm = "AM";
string returnValue = string.Empty;
if (timeSpanFormat == TimeSpanFormat.AmPm)
{
if (hours >= 12)
{
AmOrPm = "PM";
}
if (hours > 12)
{
hours -= 12;
}
TimeSpan timeSpanAmPm = new TimeSpan(hours, minutes, 0);
returnValue = timeSpanAmPm.ToString(#"h\:mm") + " " + AmOrPm;
}
else
{
returnValue = timeSpan.ToString(#"h\:mm");
}
return returnValue;
}

C# Is it possible to convert DateTime format to integer or float?

I'm having some trouble here.
Did some research on Google but I can't seem to find what I'm looking for.
I'm trying to ask for two inputs (datetimes) in hh:mm format, subtract one for the other then return the result of that value in minutes.
The problem is that I want to return that value as an integer and I can't seem to find the right way to do it.
In C/C++ I wouldn't have this kind of issues...
Anyways, here's a snippet of what I'm talking about.
private int DuraçaoTreino(DateTime dtInicioTreino, DateTime dtFimTreino, int dtDuraçao)
{
Console.WriteLine("Introduza a hora de inicio (hh:mm): ");
dtInicioTreino = Convert.ToDateTime(Console.Read());
Console.WriteLine("Introduza a hora de fim (hh:mm): ");
dtFimTreino = Convert.ToDateTime(Console.Read());
dtDuraçao = (dtFimTreino - dtInicioTreino); // duração da sessão de treino
dtDuraçao = Convert.ToDecimal(Console.Read());
return dtDuraçao;
}
And that's pretty much it... I'm new to C# so if you see anything wrong please be kind.
Thanks in advance.

What you're talking about is a TimeSpan:
DateTime dtBegin = new DateTime(2011,5,1,22,0,0) ; // 10pm 1 May 2011
DateTime dtEnd = new DateTime(2011,5,1,23,0,0) ; // 11pm 1 May 2011
TimeSpan tmElapsed = dtEnd - dtBegin ; // tmElapsed is a TimeSpan with a value of 60 minutes
To return the minutes, do something like:
int elapsedTimeInMinutes = (int) Math.Round( tmElapsed.TotalMinutes , 0 ,MidpointRounding.ToEven ) ;

var timeInMinutes = new DateTime(2011, 12, 25).Subtract(new DateTime(2010, 1, 1)).TotalMinutes;
Instead of creating the DateTime objects using the constructor I used, you can use DateTime.Parse, or better still DateTime.ParseExact to convert the strings to date times. (I know I am only using date parts here but you choose only to use time parts if you wish)

Convert DateTime objects to TimeSpan's, substract and call TimeSpan.TotalMinutes (or smth like that - dont' have VS at hand):
DateTime dt1, dt2;
// Assign some dates, then:
TimeSpan ts = dt2 - dt1;
double minutes = ts.TotalMinutes;