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 valid

Answer 1

As an alternative, you can use CompareValidator instead of RegularExpressionValidator. It goes like this:

<asp:CompareValidator ID="CompareValidator2" runat="server" ControlToValidate="txtIssueDate" ErrorMessage="Invalid Date Format" Type="Date" Operator="DataTypeCheck" Display="Dynamic" Text="*" ForeColor="Red" ValidationGroup="valGroup1"></asp:CompareValidator>

Answer 2

The above regular expression is correct for dd/mm/yyyy format. the expression is

(^((((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}))))$)

Answer 3

Last answer is actually the correct way to do. Use DateTime.TryParse.

Example:

DateTime dt;
if(DateTime.TryParse(Textbox1.Text,out dt))
{
 Label1.Text = "Invalid date format";
}

Answer 4

([0][1-9]|[1][0-9|][2][0-9]|[3][0-1])\/([0][1-9]|[1][0-2])\/[1-2][0-9][0-9][0-9]

for dd/mm/yyyy (year can be from 1000 to 2999)

or

(([0][1-9]|[2][0-9]|[3][0-1]|[1-9]|[1][0-9])/([0][1-9]|[1][0-2]|[1-9])/([1-2][0-9][0-9][0-9]|[0-9][0-9]))

which includes d/m/yy (e.g. 1/12/82)

Answer 5

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 6

You can use DateTime.TryParseExact:

DateTime dt;

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