C# Regular Expression to validate a date?

Question

I am trying to validate a date entered into a text box. There is an input mask on the textbox which forces input of xx/xx/xxxx. I am trying to use a regular expression validator to enforce that a correct date is entered. I am not skilled in RegEx bascially at all. My co-worker found this one on the internet but I can't really tell what it's doing.

Does this look right? Seems overly complicated...

(^((((0[1-9])|([1-2][0-9])|(3[0-1]))|([1-9]))\x2F(((0[1-9])|(1[0-2]))|([1-9]))\x2F(([0-9]{2})|(((19)|([2]([0]{1})))([0-9]{2}))))$)

Does anyone know of a less complex expression that essentially does what I need?

Thanks, ~ck in San Diego

Answer 1

This has been addressed in this post. See if it helps.

Answer 2

Why not use one of the methods available in the System.DateTime namespace? You could use DateTime.TryParse() (edit: DateTime.TryParseExact() is probably the right suggestion) to accomplish the validation.

Answer 3

You can use DateTime.TryParseExact:

DateTime dt;

bool isValid = DateTime.TryParseExact(
    "08/30/2009",
    "MM/dd/yyyy",
    CultureInfo.InvariantCulture,
    DateTimeStyles.None,
    out dt);

Answer 4

This isn't really an answer, but couldn't you use DateTime.Parse or DateTime.TryParse to check that the date is correct?

Either that or use a DateTime control to make sure it's impossible to enter data that isn't a DateTime. There's lots of Javascript out there on this subject.

Answer 5

Kettenbach had a problem. His co-worker suggested using regexs. Kettenbach then had two problems.

as others have said, use DateTime.TryParse or DateTime.TryParseExact on a custom validator and save yourself the nightmare that is regex :)

Answer 6

Last answer is actuallu correct way to do. Use DateTime.TryParse

Example: DateTime dt; if(DateTime.Tryparse(Textbox1.Text,Out dt) { Label1.Text = "Invalid date"; }