How to make a countdown timer to a set date in Visual Basic 2010?

In addition to the Date class in VB, there is also a TimeSpan class that tells you a lot about the difference between two dates.

To display the time remaining, you need an event time:

Dim eventDate As New DateTime(2010, 12, 25) ' Xmas

To find out how long before Christmas, subtract eventDate from current date and store it in a TimeSpan:

Dim ts As New TimeSpan

ts = eventDate - Date.Now

A TimeSpan has fields with Days, Hours, Minutes, Seconds etc. So you can display those:

tb1.Text = ts.Days.ToString() ' Days remaining

tb2.Text = ts.Hours.ToString() ' Hours remaining

etc....

For a progress bar, you need 3 dates. Some start date, the current date, and the end date. (You can't do a progress bar with only 2 dates...think about it ;-)

If you have a start date, then you can compute how far along you are using the Ticks field. Compute total ticks between start date and now. Divide by Ticks between end date and start date. Multiply by 100 and that will give you the % of the way there, which you can map to a progress bar. Something like this(off the top of my head):

Dim d As Double

d = 100 * (Date.Now - startDate).Ticks / (eventDate - startDate).Ticks

You can update your time remaining and progress bar from a timer event if this is a Win app. For a web app you just do it on every page refresh (and use Javascript to keep it running in between?)

Don't forget to handle the case that Date.Now > eventDate. Otherwise you'll end up displaying that there are -1 days left until Christmas :-(

Countdown Timer To Date