Develop Reference

How to parse a timespan in order to add it to a datetime?

I've got a string in the following format: 05/06/2019|1330|60
The output I'm looking for is: 05/06/2019T14:30:00
I'm attempting to parse out the TimeSpan portion right now:
public static string getProcedureEndingDateTime (string input) {
//05/06/2019|1330|60
string myDate = input.Split ( '|' ) [0];
DateTime myDateTime = DateTime.Parse (myDate);
string myTime = input.Split('|')[1];
string hours = myTime.Substring(0,2);
string minutes = myTime.Substring(2,2);
TimeSpan myTimeSpan = TimeSpan.Parse($"{hours}:{minutes}");
myDateTime.Add(myTimeSpan);
return myDateTime.ToString();
}
But right now, getting the following output:
To get the above output I'm calling my function like so:
Console.WriteLine (getProcedureEndingDateTime("05/06/2019|1330|60"));
How do I parse the string "1330" into a TimeSpan?

No need to us a Timespan here, just call ParseExact instead with a proper format to do it in one line.
var myDateTime = DateTime.ParseExact("05/06/2019|1330|60", "dd/MM/yyyy|HHmm|60", CultureInfo.InvariantCulture);
Console.WriteLine(myDateTime.ToString());
//this gives 2019-06-05 1:30:00 PM, format depends on your PC's locale
I don't know what the 60 part is, you can adjust the format or substring it out beforehand.

The problem is because Add() returns a new DateTime instance, which means you're currently discarding it. Store it, and return that from your function instead, like so:
var adjusted = myDateTime.Add(myTimeSpan);
return adjusted.ToString();

Try using the numeric values as exactly that, numbers.
Also, the other issue with your code is the DateTime.Add() method doesn't add to that DateTime variable. Instead it returns a new variable, which you are ignoring.
Try this:
public static string getProcedureEndingDateTime (string input) {
string[] parts = input.Split('|');
string myDate = parts[0];
DateTime myDateTime = DateTime.Parse (myDate);
string myTime = parts[1];
if (!int.TryParse(myTime.Substring(0,2), out int hours))
hours = 0;
if (!int.TryParse(myTime.Substring(2,2), out int minutes))
minutes = 0;
TimeSpan myTimeSpan = new TimeSpan(hours, minutes, 0);
myDateTime += myTimeSpan;
return myDateTime.ToString();
}

Assuming the date shown is May 6th (and not June 5th), and also assuming the 60 represents a time zone offset expressed in minutes west of GMT, and also assuming you want the corresponding UTC value, then:
public static string getProcedureEndingDateTime (string input) {
// example input: "05/06/2019|1330|60"
// separate the offset from the rest of the string
string dateTimeString = input.Substring(0, 15);
string offsetString = input.Substring(16);
// parse the DateTime as given, and parse the offset separately, inverting the sign
DateTime dt = DateTime.ParseExact(dateTimeString, "MM/dd/yyyy|HHmm", CultureInfo.InvariantCulture);
TimeSpan offset = TimeSpan.FromMinutes(-int.Parse(offsetString));
// create a DateTimeOffset from these two components
DateTimeOffset dto = new DateTimeOffset(dt, offset);
// Convert to UTC and return a string in the desired format
DateTime utcDateTime = dto.UtcDateTime;
return utcDateTime.ToString("MM/dd/yyyy'T'HH:mm:ss", CultureInfo.InvariantCulture);
}
A few additional points:
Not only is the input format strange, but so is your desired output format. It is strange to see a T separating the date and time and also see the date in the 05/06/2019 format. T almost always means to use ISO 8601, which requires year-month-day ordering and hyphen separators. I'd suggest either dropping the T if you want a locale-specific format, or keep the T and use the standard format. Don't do both.
In ISO 8601, it's also a good idea to append a Z to UTC-based values. For DateTime values, the K specifier should be used for that. In other words, you probably want the last line above to be:
return utcDateTime.ToString("yyyy-MM-dd'T'HH:mm:ssK", CultureInfo.InvariantCulture);
// outputs: "2019-05-06T14:30:00Z"
You might want to not format a string here, but instead return the DateTime or DateTimeOffset value. It's usually better to create a string only at the time of display.
Don't forget that the DateTime struct is immutable. In your question you were ignoring the return value of the Add method.

How to convert string into date time with milliseconds in C#

How do I convert this string into a date time with milliseconds
03/04/2019 15:16:57.73
The format is day/month/year hour:minutes:seconds.milliseconds.
I tried it like this:
var format = "dd/MM/yyyy HH:mm:ss.fff";
var year = dateTime.Substring(0, 4);
var month = dateTime.Substring(4, 2);
var day = dateTime.Substring(6,2);
var hour = dateTime.Substring(8, 2);
var minute = dateTime.Substring(10, 2);
var seconds = dateTime.Substring(12, 2);
var miiliseconds = dateTime.Substring(14, 2);
var stringDate = $#"{day}/{month}/{year} {hour}:{minute}:{seconds}.{miiliseconds}";
var transactioDateTime = DateTime.ParseExact(stringDate, format, CultureInfo.InvariantCulture);
But I get an error of
Additional information: String was not recognized as a valid DateTime.
Can you please help me with this? Thank you.

Seems like you don't need substrings at all.
Just put your date string right into ParseExact and you will get what you want.
However the error there is because you have different milliseconds format: it expects you will put three digits there but you passed only two:
var dateTime = "03/04/2019 15:16:57.73";
var format = "dd/MM/yyyy HH:mm:ss.ff"; - this is the fix.

Assign value of a string (containing date and time) to two different variable (one for Date and one for Time)

I have a string ("CompletionDate") which contains the value "2/28/2017 5:24:00 PM"
Now I have 2 variables (EDate and ETime). I want to assign the Date to EDate (i.e 2/28/2017) and Time to ETime (i.e. 5:24:00 PM).
How can I split the Date and Time from a single string.
Kindly Help.
My approach right now is like :
string CompletionDate = string.Empty;
string ProjectEDate = string.Empty;
string ProjectETime = string.Empty;
CompletionDate = "2017-03-29 12:58:00";
DateTime dt = DateTime.ParseExact(CompletionDate, "yyyy-MM-dd", CultureInfo.CreateSpecificCulture("en-us"));
DateTime dt1 = DateTime.ParseExact(CompletionDate, "HH:mm:ss", CultureInfo.CreateSpecificCulture("en-us"));
var ProjectEDate = dt.ToString();
var ProjectETime = dt1.ToString();
But its throwing exception that string is not in correct format. Kindly help

#Chris pointed one of your problems, but you have one more. You are passing full date time string and trying to treat it as date or time only, which is not true. Instead I suggest you to parse DateTime object with both date and time, and then take whatever you need from parsed object:
CultureInfo enUS = CultureInfo.CreateSpecificCulture("en-us");
DateTime dt = DateTime.ParseExact(CompletionDate, "yyyy-MM-dd HH:mm:ss", enUS);
var ProjectEDate = dt.Date.ToString();
var ProjectETime = dt.TimeOfDay.ToString();

You need to specify the full format as same as the input string to parse method.
DateTime dt = DateTime.ParseExact(CompletionDate, "yyyy-MM-dd HH:mm:ss", System.Globalization.CultureInfo.CreateSpecificCulture("en-us"));
To get results you can use below methods available by default in DateTime.
dt.ToShortTimeString()
"12:58 PM"
dt.ToLongTimeString()
"12:58:00 PM"
dt.ToLongDateString()
"Wednesday, March 29, 2017"
dt.ToShortDateString()
"3/29/2017"
Or you can specify the format to ToString method.
dt.ToString("yyyy-MM-dd")
"2017-03-29"
dt.ToString("HH:mm:ss")
"12:58:00"

DateTime.ParseExact(CompletionDate, "yyy-MM-dd", ...
You are missing 4th 'y' in date format string:
"yyyy-MM-dd"
^
here
and:
String was not recognized as a valid DateTime " format dd/MM/yyyy"

Why do you parse into DateTime and then convert to a string using ToString again? Couldn´t you just simply use String.Split when all you want is to split the time from the day and you know the exact format?
var CompletionDate = "2017-03-29 12:58:00";
var tmp = CompletionDate.Split(' ');
var ProjectEDate = tmp[0];
var ProjectETime = tmp[1];

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;
}

asp.net DateTime manipulation

I have various strings of type: 7/12/2012 12:02:39 AM
and would like to convert them all to just 7/12/2012 12:00:00 AM
Basically the date needs be the same, just the time must be set to 12:00:00 AM for all.
What is the best way to approach that? Except just looking for " " and replacing with 12:00:00 AM

First, parse them to a DateTime. Then you can use the Date property(0h) and parse it back to a String by using DateTime.ToString:
var oldDate = DateTime.Parse("7/12/2012 12:02:39 AM");
var usCulture = System.Globalization.CultureInfo.CreateSpecificCulture("en-US");
var newDateStr = oldDate.Date.ToString( usCulture );
Custom Date and Time Format Strings
only just noticed that 12 AM is midnight not highnoon
You can create new DateTime instance via constuctor:
var newDate = new DateTime(oldDate.Year, oldDate.Month, oldDate.Day, 12, 0, 0);
or by adding 12 hours to the date part of the DateTime(0h):
var newDate = oldDate.Date.AddHours(12);

Parse them as DateTime
Write them back to string using yourDateTime.Date.ToString(#"G", CultureInfo.CreateSpecificCulture("en-us"))

use DateTime.Parse and specify the CulterInfo
DateTime mydat = DateTime.Parse(myString, CultureInfo.InvariantCulture);