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Can i convert a string in format Mddyyy to datetime object c# core

I trying to parse a string like 4212021 where 4 is the month, 21 is the day, and 2021 is the year, into a DateTime object. I've tried using the following code but for some reason I am getting 'String '4212021' was not recognized as a valid DateTime.':
string datetimestring = "4122021";
var date = DateTime.ParseExact(datetimestring, "Mddyyyy", CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal);
All help is appreciated. Thanks.

This doesn't work without date separators. So you could add them:
string format = "Mddyyyy";
CultureInfo culture = CultureInfo.InvariantCulture;
string separator = culture.DateTimeFormat.DateSeparator;
if(datetimestring.Length >= format.Length)
{
int firstIndex = datetimestring.Length % 2 == 0 ? 2 : 1;
datetimestring = datetimestring.Insert(firstIndex, separator);
datetimestring = datetimestring.Insert(firstIndex + 2 + separator.Length, separator);
}
DateTime date = DateTime.Parse(datetimestring, culture, DateTimeStyles.None);
This works also if the month has two digits like in "12122021".
Another, maybe simpler way was to use ParseExact with "Mddyyyy HHmmss" and append zero time:
datetimestring = datetimestring + " 000000"; // check first length ofc
DateTime date = DateTime.ParseExact(datetimestring, "Mddyyyy HHmmss", culture, DateTimeStyles.None);

It's just the "M" modificator that does not work if you use it without separators AND with variable length. If you ensure leading zeros, it should work. ("04" instead of "4")
string datetimestring = 4122021.ToString("D8");
var date = DateTime.ParseExact(datetimestring, "Mddyyyy", CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal);

Since your day is always 2 digits (dd) you can just append a 0 to the start of the string when the month only has 1 digit, and use the MM for month:
string datetimestring = "4122021";
var date = DateTime.ParseExact(datetimestring.PadLeft(8,'0'), "MMddyyyy", CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal);

I am imagining you have a special reason for not changing the input. You can try this way, it will work.
string datetimestring = "4122021";
var date = DateTime.ParseExact(datetimestring.Length < 8 ? $"0{datetimestring}" : datetimestring, "Mddyyyy", CultureInfo.InvariantCulture, DateTimeStyles.AssumeLocal);
See if it is appropriate for your context?

How to convert date to 'ccyymmddhhmmss' format?

How to convert date to 'ccyymmddhhmmss' format in c#?

You might want to try this... I don't know if cc is included, so I solved for the cc.
DateTime time = DateTime.Now;
string format = "yyMMddhhmmss";
Console.WriteLine(((Convert.ToInt32(time.ToString("yyyy")) / 100) + 1).ToString() + time.ToString(format));
For "yyMMddhhmmss".....Try this...And don't forget that capital M is Month and lower case m is minutes.
DateTime dt = Convert.ToDateTime("8 Oct 10 19:00");
Console.WriteLine(dt.ToString("yyMMddhhmmss"));

From what I understand from your question, you want to format a c# date object to the specified format?
The easiest way to do that is by using the date.ToString("yyyyMMddHHmmss") - where date is the Date Object... There are several choices to this - like having 12-hour instead of 24-hour etc. The best option is to read through http://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110).aspx and set what you need.
Hope this helps.

#Chris_techno25: I took the freedom to extend your answer:
If we stick to the question of Narashima, he wants the format ccyymmddhhmmss.
So I've scratched up this extension method:
public static string IncludeCentury(this DateTime sourceDate, bool replace)
{
var source = String.Format("{0}/{1}", sourceDate.Year / 100 + 1, sourceDate);
if(replace)
return Regex.Replace(source, "[^0-9]", "");
else
return source;
}
Usage:
var includingCentury = DateTime.Now.IncludeCentury(true)
var includingCentury = DateTime.Now.IncludeCentury(false)
Output:
21218201491410
21/2/18/2014 9:18:10 AM

String To DateFormat Conversion

Is there any way I don't have to specify the number of digits in day/month/year?
For e.g 1/2/1991
I want a method which satisfies both 1/2/1991,11/3/1990,12/12/1991
I don't know how many digits will be there in either month, year, or days.
My code is
string copy = splittedData[0] + splittedData[1] + splittedData[2];//date+month+year
DateTime datetime = DateTime.ParseExact(copy, "ddMMyyyy", CultureInfo.InvariantCulture);
DateTime dateAndTime = datetime;
The problem is the number of digits in splitted data array are not known to me and thus the above format "ddMMyyyy" give me exception on some cases.

Since you already have the day month and year then just create a date with the three of them like so;
DateTime date = new DateTime(year, month, day);
No parsing is necessary. You already have all the fields you want to create the date, and you dont need to put it into a special format to create a date.
If you are not sure the if the input is valid, then wrap the creation in a try/catch block to catch an ArgumentOutOfRangeException should it should occur.

Since you updated your question with the code you have, you can concatenate date components with a separator like:
string copy = splittedData[0] + "/" + splittedData[1] + "/" + splittedData[2];
Later you can do:
DateTime dt = DateTime.ParseExact(copy, "d/M/yyyy", CultureInfo.InvariantCulture);
I used the format "d/M/yyyy" with single d and M which would account for both single/double digit day/month.
So it will work for dates like:
01/01/2013
1/01/2013
22/09/2013
02/9/2013

DateTime.ParseExact is specifically intended to not allow what you are asking for. DateTime.Parse will allow it, though.
You say you have the 3 parts as separate strings -- if you insert the /'s and parse, it should succeed (InvariantCulture expects the order month-day-year):
string datetimeString = string.Join("/", new[] {month, day, year});
DateTime datetime = DateTime.Parse(datetimeString, CultureInfo.InvariantCulture);
Or you could convert them to integers and construct a DateTime directly:
DateTime datetime = new DateTime(Convert.ToInt32(year), Convert.ToInt32(month), Convert.ToInt32(day));

What #n00b said. You've already got the individual components of the date: why are you globbing them back together just so you can call DateTime parsing routines? Just do something like this:
private static DateTime StringToDateTime( string year , string month , string day )
{
int yyyy = int.Parse(year) ;
int mm = int.Parse(month) ;
int dd = int.Parse(day) ;
DateTime dt = new DateTime(yyyy,mm,dd) ;
return dt ;
}
As an added bonus, The above code will probably run faster than DateTime.Parse() or DateTime.ParseExact().

Formatting any string to string "yyyy/MM/dd" [duplicate]

This question already has answers here:
Date formatting yyyymmdd to yyyy-mm-dd
(9 answers)
Closed 5 years ago.
I have many strings like "20120117" and "20120321". I need to convert it in a new string with this format: "2012/01/17" and "2012/03/21". So, there is a way to do this?
I try:
string dateString = string.format("{0:d", "20120321");
and
string dateString = string.format("{0:yyyy/MM/dd", "20120321");
and
string dateString = int.Parse("20120321").ToString("yyyy/MM/dd");
I all cases i don't reach my goal. =/
So, i can i do this?
OBS: There is a way to do that without parse to datetime?

You have to parse those values in DateTime objects first.
Example :
DateTime dt = DateTime.ParseExact("20120321", "yyyyMMdd", System.Globalization.CultureInfo.InvariantCulture);
var result = dt.ToString("yyyy/MM/dd");
Edit after your comments on other answers:
if you don't like parsing because it may throw excepations, you can always use TryParse, like this:
DateTime dt;
bool success = DateTime.TryParseExact("20120321", "yyyyMMdd", System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out dt);
if (success)
{
var result = dt.ToString("yyyy/MM/dd");
}
Edit 2: Using TryParseExact with multiple formats:
DateTime dt;
string[] formats = { "yyyyMMdd", "yyyy" };
bool success = DateTime.TryParseExact("20120321", formats, System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out dt);
if (success)
{
var result = dt.ToString("yyyy/MM/dd");
Console.WriteLine(result);
}
It will produce 2012/03/21 when using "20120321" as input value, and 2012/01/01 when using 2012 as input value.

DateTime.ParseExact("20120321", "yyyyMMdd", CultureInfo.CurrentCulture).ToString("yyyy/MM/dd")
You could parse the string but this method gives you validation without any extra code. Imagine receiving "20120230", "20110229", or any other invalid date.

From your comments:
There is a way to do that without parse to datetime?
Yes, absolutely. If you really want to propagate bad data through your system rather than highlighting that it's incorrect, you could definitely use:
// Make sure we'll always be able to get a result whatever the input.
string paddedInput = input + "????????";
string mightBeBadWhoKnows = string.Format("{0}/{1}/{2}",
paddedInput.Substring(0, 4), // The year, if we're lucky
paddedInput.Substring(4, 2), // The month, if we're lucky
paddedInput.Substring(6, 2)); // The day, if we're lucky
But why wouldn't you want to spot the bad data?
You absolutely should parse the data. If you want to be able to continue after receiving bad data having taken appropriate action, use DateTime.TryParseExact. If you're happy for an exception to be thrown, use DateTime.ParseExact. I'd suggest using the invariant culture for both parsing and formatting, unless you really want a culture-sensitive output.

Use DateTime.ParseExact to convert to a DateTime, then use ToString on that instance to format as you desire.
DateTime.ParseExact(dateString, "yyyyMMdd").ToString("yyyy/MM/dd");
EDIT: using Insert:
EDIT2: Fixed bugs :-)
var newString = dateString.Insert(4, "/").Insert(7, "/");

Just use string operations to insert the slashes:
string input = "20120321";
string dateString =
input.Substring(0, 4) + "/" +
input.Substring(4, 2) + "/" +
input.Substring(6);
or
string dateString = input.Insert(6, "/").Insert(4, "/");

If it's a date, try this:
DateTime.ParseExact("20120321","yyyyMMdd", null).ToString("yyyy/MM/dd", System.Globalization.DateTimeFormatInfo.InvariantInfo)

try this;
string dateString = DateTime.ParseExact("20120321", "yyyyMMdd",
null).ToShortDateString();

If your data is always in the same format and if you don't need to validate it, you can use the following snippet to avoid parsing it with DateTime
var strWithInsert = input.Insert(4,"/").Insert(7,"/");

Convert month int to month name

I was simply trying to use the DateTime structure to transform an integer between 1 and 12 into an abbrieviated month name.
Here is what I tried:
DateTime getMonth = DateTime.ParseExact(Month.ToString(),
"M", CultureInfo.CurrentCulture);
return getMonth.ToString("MMM");
However I get a FormatException on the first line because the string is not a valid DateTime. Can anyone tell me how to do this?

CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(1);
See Here for more details.
Or
DateTime dt = DateTime.Now;
Console.WriteLine( dt.ToString( "MMMM" ) );
Or if you want to get the culture-specific abbreviated name.
GetAbbreviatedMonthName(1);
Reference

var monthIndex = 1;
return month = DateTimeFormatInfo.CurrentInfo.GetAbbreviatedMonthName(monthIndex);
You can try this one as well

You can do something like this instead.
return new DateTime(2010, Month, 1).ToString("MMM");

CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(
Convert.ToInt32(e.Row.Cells[7].Text.Substring(3,2))).Substring(0,3)
+ "-"
+ Convert.ToDateTime(e.Row.Cells[7].Text).ToString("yyyy");