Convert VB.Net Textbox input to Time of Day

Question

I am creating an application that needs to allow the user to input a 4-digit text string (ex. 1330 or 0100) and convert that input to the time of day including AM/PM.

examples 1330 = 1:30 PM; 0130 = 1:30 AM

I am unsure what the best way to go about this would be. I am thinking to use a select case or nested ifs; however, I feel as if there is probably a better, quicker way to convert this. Any help will be much appreciated. Thank you in advance.

Answer 1

One possibility would be to use the DateTimePicker control from the Extended WPF Toolkit or create your own simple user control with for example two fields for the hour and minute parts.

If you want to create your own solution:

• make sure, that the input is always 4 characters long
• create a string from the current date and the entered time stamp
• verify and parse the string with DateTime.TryParse
• use the new DateTime object to take the time
• use DateTime.ToString(format,provider) to create the desired output

The code to parse the user input string:

private Function parseTime(ByRef hours as String) as String
    ' TODO: error handling
    Dim timeStamp as String = String.Format("{0} {1}:{2}", System.DateTime.Now.ToShortDateString(), hours.Substring(0, 2),hours.Substring(2, 2))
    Dim dateTime as DateTime
    if (DateTime.TryParse(timeStamp, dateTime)) then
        return String.Format("{0}{1}", dateTime.ToString("hh:mm", CultureInfo.InvariantCulture), dateTime.ToString("tt", CultureInfo.InvariantCulture))
    end if

    return String.Empty

end Function

Usage:

Dim hoursPM as String = "1330"
Dim hoursAM as String = "0130"
Console.WriteLine(parseTime(hoursPM))
Console.WriteLine(parseTime("errr")) 'empty string indicates error
Console.WriteLine(parseTime(hoursAM))

And the output:

01:30PM

01:30AM