A Calculator Project in VB NET

In the next few pages, you're going to create a Calculator. It won't be a very sophisticated calculator, and the only thing it can do is add up. What the project will give you is more confidence in using variables, and shifting values from one control to another. So create a new project, call it Calculator, and let's get started.


Designing the Form

Let's design the form first. What does a calculator need? Well numbers, for one. A display area for the result. A plus sign button, an equals sign button, and a clear the display button.

Here's how our calculator is going to work. We'll have 10 button for the numbers 0 to 9. When a button is clicked its value will be transferred to a display area, which will be a Textbox. Once a number is transferred to the Textbox we can click on the Plus button. Then we need to click back on another number. To get the answer, we'll click on the equals sign. To clear the display, we'll have a Clear button.

If you haven't already, create a new project. Save it as Calculator. To your new form, first add ten Buttons (You can add one, then copy and paste the rest). The Buttons should have the following Properties:

Name: btn Plus a Number (btnOne, btnTwo, btnThree, etc)

Text: A number from 0 to 9. A different one for each button, obviously

Font: MS Sans Serif, Bold, 14

Next, add a Textbox. Set the following properties for the Textbox:

Name: txtDisplay
Font: MS Sans Serif, Bold, 14
Text: Erase the default, Textbox1, and leave it blank

Three more buttons need to be added

Plus Button
Name: btnPlus
Font: MS Sans Serif, Bold, 14
Text: +

Equals Button
Name: btnEquals
Font MS Sans Serif, Bold, 14
Text: =

Clear Button
Name: btnClear
Font MS Sans Serif, Bold, 14
Text: Clear

When your form design is finished, it might look something like this:

Calculator form in NET

So if you wanted to add 5 + 9, you would click first on the 5. A 5 would appear in the textbox. Then you would click the + symbol. The 5 would disappear from the textbox. Next, click on the 9. The number 9 would appear in the textbox. Finally, click on the = symbol. The 9 would disappear from the textbox, and the answer to our sum would replace it. We would then click the Clear button to clear the display.

In the next section, we'll make a start on the VB NET code for the all those buttons.