Parse string value to datetime value

Question

I need to parse string value to date time value, I have date in this format:

DD.MM.YYYY

I want to parse value in this format:

YYYY-MM-DD

I tried to do it like this:

DateTime.ParseExact(date_req, "yyyy-MM-dd", CultureInfo.InvariantCulture); 

But i have an error: String was not recognized as a valid DateTime.

Is there a way to do this?

Answer 1

If you have a string in the format DD.MM.YYYY why are you passing YYYY-MM-DD to your ParseExact function?

Try like this:

string dateStr = "12.06.2012";
DateTime date = DateTime.ParseExact(dateStr, "dd.MM.yyyy", CultureInfo.InvariantCulture);

Then when you want to output this DateTime instance somewhere you could use the YYYY-MM-DD format, like this:

string result = date.ToString("yyyy-MM-dd");

Answer 2

When parsing a date you need to specify the format you want to read , not the format you want as output later.

So use dd.MM.yyyy as argument to ParseExact .

Answer 3

Check DateTime.ParseExact Method (String, String, IFormatProvider) 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.

you have to specify format string as DD.MM.YYYY rather than "yyyy-MM-dd" .

try this:

DateTime dateValue = DateTime.ParseExact(date_req, "DD.MM.YYYY", CultureInfo.InvariantCulture );

// use this when you need to show that formatted date value
string formattedDate = dateValue.ToString("yyyy-MM-dd");

Better way is that use DateTime.TryParseExact Method , if you want it as date rather than string modify your culture info and date separator.

CultureInfo enUS = new CultureInfo("en-US"); 
string dateString;
DateTime dateValue;
dateString = "05.01.2009"; 
if (DateTime.TryParseExact(dateString, "DD.MM.YYYY", enUS, 
                        DateTimeStyles.None, out dateValue))
   Console.WriteLine("Converted '{0}' to {1} ({2}).", dateString, dateValue, 
                     dateValue.Kind);
else
   Console.WriteLine("'{0}' is not in an acceptable format.", dateString);

Answer 4

I think what you want to do is parse your dd.MM.yyyy and then display it as yyyy-MM-dd .

You first have to parse the string into a DateTime :

DateTime date = DateTime.ParseExact(date_req, "yyyy-MM-dd", CultureInfo.InvariantCulture); 

Now date is a representation of the date that the computer actually understands (before it was just a string). You can now display this object anyway you want:

string yyyyMMdd = date.ToString("yyyy-MM-dd");
string arabic = date.ToString("yyyy-MM-dd", new CultureInfo("ar"));
// and so on

Don't forget that when converting dates from strings to DateTime and back, culture and time zones are worth keeping in mind.

Answer 5

First parse it in the existing format then convert to the string format you want.

var date = DateTime.ParseExact(date_req, "dd.MM.yyyy", CultureInfo.InvariantCulture); 
var str = date.ToString("yyyy-MM-dd");

Answer 6

You can first convert it to a character array. then you can parse day/month/year separately to integers . You know the indexes of the numbers so this will be easy. after that you can concatenate every element in the way you like.

Answer 7

Error. You have a cake and you want to eat a stake. In order to convince your stomach that that the cake is a stake you have to transform the cake to a stake. This cannot be done. Parsing is about accepting a value as it comes and use a pattern (or more) to translate it to something else and not transform it. So what you want may be right but you ask is wrong.