Validating a date format string in c#

Question

I want users to be able to enter a date format string in a text box so they can specify how they want a date value to be Displayed in their windows form

How can I validate this date format string entered in a text box so that they can enter only a valid C# Date format

Give all the valid formats in the combo instead. Easy for user and you both — Mohit S, Dec 02 '16 at 04:26
@ Mohit Shrivastava i tried it ..but it seems to be a very long list — Anjitha, Dec 02 '16 at 04:31
You will get all possible DateTime formats from [Here](https://msdn.microsoft.com/en-us/library/8kb3ddd4(v=vs.110).aspx) populate those values to a ComboBox as My friend Mohit suggest. so that your users can select a format from that list — sujith karivelil, Dec 02 '16 at 04:34
see [this](http://stackoverflow.com/questions/15491894/regex-to-validate-date-format-dd-mm-yyyy) post where it validates for date formats like dd/mm/yyyy,dd-mm-yyyy or dd.mm.yyyy — kashi_rock, Dec 02 '16 at 04:35

score 1 · Accepted Answer · answered Dec 02 '16 at 05:37

For a valid date, you need date (dd), month (mm) and year(yyyy). I can give you a simple regex, for validating dates like dd/mm/yy or dd.mm/yyyy

(dd|mm|yy{2,4}?).(dd|mm||yy{2,4}?).(dd|mm||yy{2,4}?)

It passes for any combination of dd,mm and yyyy or yy.

It also accepts dd.dd.mm or anything like that. So, Make sure you check for multiple occurrences of characters.

score 0 · Answer 2 · answered Dec 02 '16 at 07:16

You can use DateTime.TryParse and check whether the entered date time string is valid or not.

Here is the code:

DateTime dt;
string myDate = "2016-12-10";
bool success = DateTime.TryParse(myDate, out dt);
Console.WriteLine(success);

Console.WriteLine(DateTime.TryParse("2016-12-10", out dt));    //true
Console.WriteLine(DateTime.TryParse("10-12-2016", out dt));    //true
Console.WriteLine(DateTime.TryParse("2016 July, 01", out dt));    //true
Console.WriteLine(DateTime.TryParse("July 2016 99", out dt));    //true

This addresses the question of validating a user-supplied _date_ but not a user-supplied date _format_. — JYelton, Feb 28 '17 at 18:24

Validating a date format string in c#

2 Answers2

Linked