Visual Basic | Lists exercise | Create a list of dates which are on Friday 13th

This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.

Software ==> Visual Basic  (46 exercises)
Version ==> Any version of VB
Topic ==> Lists  (3 exercises)
Level ==> Average difficulty
Subject ==> Visual Basic training
Before you can do this exercise, you'll need to download and unzip this file (if you have any problems doing this, click here for help).

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Press CTRL + D to add the file called frmUnluckyDates.vb from the above folder into your project (or right click on the project and choose to add it as an existing item).  Change your project's properties to make this the default form for your project. 

Attach code to the left-hand button so that when you click on it you see something like this:

List of 13th dates

Clicking on the button shown should generate a list of Friday 13ths, then set this list as the data source for the listbox. 


Some hints on how to proceed are shown below.

You can use the AddMonths method to add a given number of calendar months on to any given date.  You may also find this code excerpt useful:

'get the 13th of this month

Dim startDate As Date = System.DateTime.Today

startDate = New DateTime(startDate.Year, startDate.Month, 13)

When you've got the first button working, attach code to the Fridays only button using the FindAll lambda function (or some other method) to count only those dates which fall on a Friday:

List of Friday 13th dates

What you should see when you click on the right-hand button. 


Remembering that this is a silly superstition, touch the table for luck anyway and close down your application and any open forms. 

You can unzip this file to see the answers to this exercise, although please remember this is for your personal use only.
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