Regular Expression for Date (dd/mm/yyyy and dd-mm-yyyy) format in ASP.Net

Hi Mahesh1986,

Regular expressions should not be used for date validation. This will match date like strings, which can then be validated using a proper date library if needed.

Still i am providing you the ValidationExpression.

For dd/mm/yyyy - ValidationExpression="(0[1-9]|[12][0-9]|3[01])[/](0[1-9]|1[012])[/]\d{4}"

For dd-mm-yyyy - ValidationExpression="(0[1-9]|[12][0-9]|3[01])[-](0[1-9]|1[012])[-]\d{4}"

(0[1-9]|[12][0-9]|3[01]) For Day

(0[1-9]|1[012]) For Month

\d{4} For Year

[-] For -

[/] For /

HTML

<asp:TextBox runat="server" ID="txtDate1" placeholder="dd/mm/yyyy format only" />
<asp:RegularExpressionValidator ID="revDate1" ErrorMessage="DateFormat should be dd/mm/yyyy"
    ControlToValidate="txtDate1" runat="server" ValidationExpression="(0[1-9]|[12][0-9]|3[01])[/](0[1-9]|1[012])[/]\d{4}" />
<br />
<asp:TextBox runat="server" ID="txtDate2" placeholder="dd-mm-yyyy format only" />
<asp:RegularExpressionValidator ID="revDate2" ErrorMessage="DateFormat should be dd-mm-yyyy"
    ControlToValidate="txtDate2" runat="server" ValidationExpression="(0[1-9]|[12][0-9]|3[01])[-](0[1-9]|1[012])[-]\d{4}" />

Thanks for your reply.will it work for leap year validation

Mahesh1986 says:

leap year validation

 Please explain the above statement in details.

mean that expression validate date like 30/02/2020 . 

No not for leap year.

As i already told you regular expression should not be used for date validation. So you need to handle those in code behind or its better let the user to select date form calander control.