We Keep Coding

converting a string to a DateTime format

I'm trying to parse 09/01/2015 00:00:00 to the format yyyy-MM-ddThh:mm:ssZ using following method:
DateTime.ParseExact("09/01/2015 00:00:00", "yyyy-MM-ddThh:mm:ssZ", (IFormatProvider)CultureInfo.InvariantCulture);
But I'm getting String was not recognized as a valid DateTime
Can anyone tell me why? I believe 09/01/2015 00:00:00 is a valid DateTime format?

From DateTime.ParseExact
Converts the specified string representation of a date and time to its
DateTime equivalent. The format of the string representation must
match a specified format exactly or an exception is thrown.
In your case, they are not.
I assume your 09 part is day numbers, you can use dd/MM/yyyy HH:mm:ss format instead.
var dt = DateTime.ParseExact("09/01/2015 00:00:00",
"dd/MM/yyyy HH:mm:ss",
CultureInfo.InvariantCulture);
Since CultureInfo already implements IFormatProvider, you don't need to explicitly cast it.
I don't understand this. So it means I first have to correct my string
and secondly I can do a ParseExact(). I thought ParseExact could
handle the given string...
ParseExact is not a magical method that can parse any formatted string you suplied. It can handle only if your string and format perfectly matches based on culture settings you used.

Try this code:
var text = "09/01/2015 00:00:00";
var format = "dd/MM/yyyy HH:mm:ss";
var dt = DateTime.ParseExact(text, format, (IFormatProvider)CultureInfo.InvariantCulture);
You'll notice that the format must structurally match the text you're trying to parse exactly - hence the ParseExact name for the method.

The format does not match, you need to change 09/01/2015 into 2015-01-09 or theyyyy-MM-dd part into dd/MM/yyyy.

The ParseExact-method is no ultimate method that converts ANY dateformat into another one, it is simply to parse a given string into a datetime using the provided format. Thus if your inout does not match this format the method will throw that exception.
As a datetime is internally only a number there is no need to convert one format into another at all, so as long as you know your input-format you can build a date from it which has nothing to do with any formatting which you may need when you want to print that date to your output. In this case you WILL need a formatter.

As most people have stated the error is coming from the fact that the date in string format doesn't match the format you are saying it's in. You are saying that 09/01/2015 00:00:00 is in the format "yyyy-MM-ddThh:mm:ssZ", which it's not, hence the error. To rectify this you need to either alter the format the string is in, or more likely, change the format you are saying the date is in. So change "yyyy-MM-ddThh:mm:ssZ" to "dd/MM/yyyy HH:mm:ss".
In a more long term view how are you arriving at that date? Is it possible that the format may change (input but the user)? If so it might be better to try and avoid the error being thrown and handle it better with TryParseExact. To make use of this best I generally output a nullable DateTime and then check if it's null. If you don't do this then if the parse fails it will simply make the output datetime the minimum value.
Something like this should work:
public DateTime? StringToDate (string dateString, string dateFormat)
{
DateTime? dt;
DateTime.TryParseExact(dateString, dateFormat, null, System.Globalization.DateTimeStyles.None, out dt);
return dt;
}
Then you can use it like this:
DateTime? MyDateTime = StringToDate("09/01/2015 00:00:00", "dd/MM/yyyy HH:mm:ss");
if(MyDateTime != null)
{
//do something
}

Another simple way to do this...
var dt = Convert.ToDateTime(Convert.ToDateTime("09/01/2015 00:00:00").ToString("yyyy-MM-ddThh:mm:ssZ"))

How to convert "2003-11-05T16:35:30Z" to "11/5/2013 " in c#?

I am having a problem while converting
2003-11-05T16:35:30Z to "11/5/2013"
I tried below
DateTime.ParseExact("2003-11-05T16:35:30Z", "dd/MM/yyyy", null)
but I am not getting the value I expect.

You want to do this:
DateTimeOffset.Parse("2003-11-05T16:35:30Z").ToString("dd/MM/yyyy")
What you're doing is parsing the data as if it were in the format dd/MM/yyyy - instead, you want to parse it as the universal format it is, and then convert it to a string with your format string.
DateTime.Parse will take a string and return a date time. To get a string back out, you simply use the ToString method.

Try This:
string myDate = DateTime.ParseExact("2003-11-05T16:35:30Z",
"yyyy-MM-ddTHH:mm:ssZ",null).ToString("M/d/yyyy");

When parsing you specify the format that you are parsing from, then you format the DateTime value using the new format:
string reformatted =
DateTime.ParseExact("2003-11-05T16:35:30Z", "yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'", null)
.ToString("dd/MM/yyyy");

C# Datetime format conversion

I have a conversion problem with datetime. I have a date string as MM/dd/yyyy. Now I need to convert it to yyyy-MM-dd.
But I'm facing some error. Please help
public static DateTime ToDBDateTime(string _dateTime)
{
string sysFormat = "MM/dd/yyyy hh:mm:ss tt";
string _convertedDate = string.Empty;
if (_dateTime != null || _dateTime != string.Empty)
{
_convertedDate = DateTime.ParseExact(_dateTime, sysFormat, System.Globalization.CultureInfo.InvariantCulture).ToString(_toDBDateFormat);
//_convertedDate = Convert.ToDateTime(_dateTime).ToString(_toDBDateFormat);
/// Debug.Print(sysFormat);
}
return Convert.ToDateTime(_convertedDate);
}
And I want to know that is there is any way to pass the datetime in various formats and it would return the expected format.
E.g.: if I pass date as dd/MM/yyyy or MM/dd/yyyy, the above function would return the date in format as yyyy-MM-dd.
Please provide some suggestion to solve datetime issues.

I have a date string as MM/dd/yyyy
Right... and yet you're trying to parse it like this:
string sysFormat = "MM/dd/yyyy hh:mm:ss tt";
...
_convertedDate = DateTime.ParseExact(_dateTime, sysFormat,
CultureInfo.InvariantCulture)
You need to give a format string which matches your input - so why are you including a time part? You probably just want:
string sysFormat = "MM/dd/yyyy";
However, that's not the end of the problems. You're then converting that DateTime back into a string like this:
.ToString(_toDBDateFormat)
... and parsing it once more:
return Convert.ToDateTime(_convertedDate);
Why on earth would you want to do that? You should avoid string conversions as far as possible. Aside from anything else, what's to say that _toDBDateFormat (a variable name which raises my suspicions to start with) and Convert.ToDateTime (which always uses the current culture for parsing) are going to be compatible?
You should:
Work out how you want to handle being given an empty string or null, and just return an appropriate DateTime then
Otherwise, just parse using the right format.
This part of your question also concerns me:
E.g.: if I pass date as dd/MM/yyyy or MM/dd/yyyy, the above function would return the date in format as yyyy-MM-dd.
There's no such thing as "the date in format as yyyy-MM-dd". A DateTime is just a date and time value. It has no intrinsic format. You specify how you want to format it when you format it. However, if you're using the value for a database query, you shouldn't be converting it into a string again anyway - you should be using parameterized SQL, and just providing it as a DateTime.

As you have a date in a string with the format "MM/dd/yyyy" and want to convert it to "yyyy-MM-dd" you could do like this:
DateTime dt = DateTime.ParseExact(dateString, "MM/dd/yyyy", CultureInfo.InvariantCulture);
dt.ToString("yyyy-MM-dd");

Use the inbuilt tostring like this:
Convert.ToDateTime(_convertedDate).ToString("MM/dd/yyyy") or whatever format you want.

I tried this and its working fine.
DateTime date1 = new DateTime(2009, 8, 1);
date1.ToString("yyyy-MM-dd hh:mm:ss tt");
You can apply any format in this ToString.
Hope that helps
Milind

how to give format DateTime.Date?

DateTime dt = DateTime.Now
dt.Date is created to 31.10.2012 00:00:00 .it is created to dd.mm.yyyy format but i need dd/mm/yyyy. Can i use: return new DateTime(d.Year, d.Month, d.Day, 0, 0, 0); it will create to me dd/mm/yyyy solution?Please dont translate String.i need datetime...

The DateTime struct doesn't store any formatting information internally. If you want to output the DateTime instance as a formatted string, you just need to call ToString() with the proper format string:
var date = DateTime.Now;
var formattedString = date.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);
If you need more information on exactly which specifiers to use in your format string, check out:
MSDN - Custom Date and Time Format Strings

Just the way to convert to string, DateTime itself has no format:
var result = DateTime.Now.Date
.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);

var dt = DateTime.Now;
var stringDt = dt.Date.ToString("dd/MM/yyyy");

In you case you can simply use :
dt.ToString("dd/MM/yyyy");
Anyway there al the string format you can use with DateTime : Here.

System.DateTime does not have any format. You can view its string representation in format.
Try this
Console.WriteLine(DateTime.Now.Date.ToString("dd'/'MM'/'yyyy"));

DateTime, numeric types and most other types do not store their values in a formatted way. Rather they store their data using a binary representation. If you want to display this data to the user, you must convert it to a string. This conversion involves formatting the data.
string formattedDate = DateTime.Now.ToString("dd/MM/yyyy",
CultureInfo.InvariantCulture);
Or
Console.WriteLine("Date = {0:dd/MM/yyyy}", DateTime.Now);
Console.WriteLine converts the date into a string in order to write it to the console.

DateTime structure always has the Date and Time stored in it. If you need to extract the date alone as text you can do the following.
var date = DateTime.Now.ToString("d");
Console.WriteLine(date);
This will print the date as in the format as specified by the culture set in the system. The list of standard datetime format strings supported by dotnet framework can be found here

Parse a string containing date and time in a custom format

I have a string of the next format "ORDER20100322194007", where 20100322 is a date and 194007 is a time. How to parse a string and get the contained DateTime object?

Will it always start with ORDER?
string pattern = "'ORDER'yyyyMMddHHmmss";
DateTime dt;
if (DateTime.TryParseExact(text, pattern, CultureInfo.InvariantCulture,
DateTimeStyles.None,
out dt))
{
// dt is the parsed value
}
else
{
// Invalid string
}
If the string being invalid should throw an exception, then use DateTime.ParseExact instead of DateTime.TryParseExact
If it doesn't always begin with "ORDER" then do whatever you need to in order to get just the date and time part, and remove "'ORDER'" from the format pattern above.

You can use DateTime.ParseExact method to specify the format that should be used while parsing.

If you don't have a fixed structure of your string say order will not always be there then you can use regex to separate the numbers and characters and then use convert to datetime function for the numbers separated.