Visual Basic Beginner Tutorial - Getting Inputs to Add Two Numbers

In this tutorial we develop a simple program which adds together two User Input Numbers.

We start with the Application Design Process for the Form and the Program Pseudocode.

We then build the first version of the Application, which uses two different methods of obtaining User Input from the Form and converting it to numeric format.
The first method involves the Val() function, and the second method involves Casting as a Double CDbl() function.

We then test the application and find there are program crashing issues if the User leaves inputs blank, or enters any non-numerical input onto the Form.

Adding Input Validation using Try.... Catch... End Try is then added to pinpoint all data input errors and send message alerts to the User.

Finally we explain why Casting combined with Validation is the superior method for obtaining User Data Inputs.


Use the Index Below to skip to various Index points in the video if you need to.

00:00 Introduction and Overview
01:32 Application Design
02:36 Form Detailed Design
05:54 Create Form in Visual Basic
16:40 Save All of Project
17:13 Program Code Version 1
21:56 Code for the Clear Button
22:54 Blank Input Problems
23:51 Running Generated Application
24:21 Difference between Val() and CDbl()
25:21 Adding Try....Catch...End Try
27:29 Using CDbl() instead of Val()
29:05 version 3 using CDbl and Try...Catch...End Try
31:01 Lesson Wrap Up and Outro

Visual Basic is a great beginner's programming language which can be used for developing prototype applications which run program code behind screen forms.

This video will be useful for anyone learning Visual Basic, especially students doing VCE Computing or VCE Software Development high school courses in Australia.

You can download a Free PDF hard copy of this presentation using the following link:
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You can download the Copy and Paste Program Code using the following link
tinyurl.com/y8ddyr3x

We are planning to make a number of Programming Videos that will be a great course for people to do to learn how to program in Visual Basic and Python.

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