Validate Date

richard smith

I have a text box on a web form where a user will input a Discharge Date...The date MUST be entered in this format MM/DD/YYYY what C# code would validate that the entry is input in that format, and if not show an error? Something like:
ButtonFinish_Click()
{
//check to see if the date is correct format
try
{
//how to check?
//if valid Response.Redirect -- Go to next page
}
catch
{
Error.Text = "Dates must be entered in a MM/DD/YYYY Format. Please check the entry and try again."

7 Replies

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Vulpes13y ago
Accepted answer
I's use something like this:

DateTime dt;
if (DateTime.TryParseExact(textBox1.Text, "MM/dd/yyyy", null, 0, out dt))
{
// it's OK and result is in 'dt'
}
else
{
// it's not OK
}
Vulpes13y ago
When you pass 'null' for that particular parameter, then the current culture is used (en-US in Richard's case).

So, with a simple date format such as MM/dd/yyyy, it doesn't matter whether you use that or the Invariant culture.
Suthish Nair13y ago

A small change... But why just use a date control.

DateTime dt1;
if (DateTime.TryParseExact(date, "MM/dd/yyyy", CultureInfo.InvariantCulture, DateTimeStyles.None, out dt1))
{
Console.WriteLine("it's OK and result is in 'dt'");
}
else
{
Console.WriteLine("it's not OK");
}
Vulpes13y ago
Are you sure that you've copied it down correctly as it's working OK for me?

Note in particular that 'dt' should be preceded by 'out' as it's an output parameter.

You can replace '0' with DateTimeStyles.None if you want to be more verbose.
richard smith13y ago
Lost me on that post. Where does that coding go? I don't think it is C# coding...

I am assuming that is javascript, and I need it to be C#
Satyapriya Nayak13y ago
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Validate_Date._Default" %>

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http://paulschreiber.com/blog/2007/03/02/javascript-date-validation/
richard smith13y ago
When I add that syntax, I get an error of:
The best overloaded method match for System.DateTime.TryParseExact(string, string, SystemIFormatProvider, System.Globalization.DateTimeStyles, out System.DateTime) has some invalid arguments.