Programming Tutorials

Handling Dates and Times in VB.net

By: Steven Holzner  

One of the biggest headaches a programmer can have is working with dates. Handling hours, minutes, and seconds can be as bad as working with shillings, pence, and pounds. Fortunately, Visual Basic has a number of date and time handling functions, which appear in Table below-you can even add or subtract dates using those functions. VB6 programmers will notice a number of new properties in this table.

Here's an example in which I'm adding 22 months to 12/31/2001 using DateAdd-you might note in particular that you can assign dates of the format 12/31/2001 to variables of the Date type if you enclose them inside # symbols:

Imports System.Math
Module Module1
    Sub Main()
        Dim FirstDate As Date
        FirstDate = #12/31/2001#
        System.Console.WriteLine("New date: " & DateAdd_
        (DateInterval.Month, 22, FirstDate))
    End Sub
End Module

Here's what you see when you run this code:

New date: 10/31/2003
Press any key to continue

There's something else you should know-the Format function makes it easy to format dates into strings, including times. For easy reference, see Table 2.11, which shows some ways to display the date and time in a string-note how many ways there are to do this.

You can also compare dates and times directly. For example, here's how you loop until the current time (returned as a string by TimeString) exceeds a certain time; when the time is up, the code beeps using the Visual Basic Beep function:

While TimeString < "15:45:00"
End While
Beep()

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