How to check if the input field is in the Time format in c#?

Question

I'm currently making an enrollment system and I want something like a [Required] (attribute?) to check if the input string is in the proper time format (18:00, 20:00, 1:00, etc.), how do I do that? Is there a function for it or will it manually have to be done? Thanks.

Answer 1

You can use RegularExpressionAttribute with the following regex:

^([01]?\d|2[0-3]):[0-5]\d$

Debuggex Demo

Answer 2

You can use a RegularExpression as validation attribute:

[RegularExpression(@"^([0-1]\d|2[0-3]):([0-5]\d)$", ErrorMessage = "invalid date format")]

The regex was found here: .NET Regular expression for time 24 hr format

Answer 3

I would suggest a method like this:

public bool IsValidTime(string time)
{
    DateTime dummyDate;
    return DateTime.TryParseExact(time, new[] { "HH:mm", "H:mm" }, 
        CultureInfo.InvariantCulture, 
        DateTimeStyles.NoCurrentDateDefault, out dummyDate);
}

This method validates 24 hour clock formats, with 1 or 2 digit hour numbers.

It gives the following results with supplied inputs:

"00:00"  => true
"20:00"  => true
"26:00"  => false
"1:00"   => true
"10:5"   => false

Answer 4

use TimeSpan.TryParse Converts the string representation of a time interval to its TimeSpan equivalent and returns a value that indicates whether the conversion succeeded http://msdn.microsoft.com/en-us/library/3z48198e(v=vs.110).aspx