WISE OWL EXERCISES
VISUAL BASIC EXERCISES
VISUAL BASIC EXERCISES
- Drawing forms (2)
- Form events (1)
- Variables and data types (2)
- Enumerations and constants (2)
- Form validation (3)
- Menus and toolbars (2)
- Files and folders (1)
- Basic DataGridViews (1)
- Reacting to DataGridView events (3)
- Advanced DataGridViews (2)
- Creating classes (4)
- Coding in VB.NET (2)
- Variables and constants (3)
- Testing conditions (2)
- Passing arguments (3)
- Using arrays (2)
- Loops (2)
- Working with files (3)
- Lists (3)
- Creating properties (3)
Visual Basic | Loops exercise | Loop over all of the controls on a form to validate them
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.
You can learn how to do this exercise on the relevant Wise Owl classroom training course (sadly for the moment only in the UK).
You need a minimum screen resolution of about 700 pixels width to see our exercises. This is because they contain diagrams and tables which would not be viewable easily on a mobile phone or small laptop. Please use a larger tablet, notebook or desktop computer, or change your screen resolution settings.
Press CTRL + D to add the file called frmApplication.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. When you run your project, you should see this:
For the exercise you'll add code to this button to validate all of the input boxes.
Sadly you can't just loop over all of the controls on the form, because some of them are hidden in the two group boxes. Because of this you need a different algorithm - a suggestion is shown below.
Here's a suggestion for how to solve our problem:
'FOR EACH CONTROL ON THE FORM
'IF IT'S A GROUPBOX (that is, if TYPEOF G IS GROUPBOX)
'FOR EACH CONTROL IN THE COLLECTION OF CONTROLS
'WITHIN THIS GROUPBOX g
'CHECK THIS CONTROL ISN'T A LABEL (NOT INTERESTED
'IF THE LENGTH OF THIS CONTROL IS 0, SET THE
'FOCUS TO THIS CONTROL AND REPORT ERROR
When you've written your code (!), check it works, then close down your application and form.