Page 48 - Computing Book 8

Developing Applications – Visual Studio Class 8

button to “Add” from the text option in the properties panel
4. Add 1 label from the toolbox in the form and change the text of the label to “Result” from
the text option in the properties panel
5. Double click on the Add button and enter this code as shown in the example below

Enter this code

Name of Variable Name of text box

Label Calculation of variables

nd
st
• The 1 and the 2 line of code are where we have declared the variables with its data type
which is an integer in this case.
th
rd
• In the 3 and 4 lines, we have declared the value of a variable. In this case, we are taking
the user input from the textbox.
th
• In the 5 line, our code adds the two variables and puts the sum as text into Label1.

6. Click on the debug button or F5 to execute the program in debugging mode.
The “=” here is an assignment operator, a symbol used to assign the value on the right of the
sign to the variable on the left. So here, the content of TextBox1 is stored in variable number1.
Note here that although whatever you write in a text box is considered as String, Visual Basic
automatically converts it to a number since the variable number1 is declared as Integer.

Common Data Types:
Common
language
Variable Type Value range
runtime type
structure
Boolean Boolean True or False
Byte Byte 0 through 255 (unsigned)
Char
(single Char 0 through 65535 (unsigned)
character)
0:00:00 (midnight) on January 1, 0001 through 11:59:59 PM on
Date DateTime
December 31, 9999
0 through +/-79,228,162,514,264,337,593,543,950,335 (+/-
7.9...E+28) with no decimal point; 0 through +/-
7.9228162514264337593543950335 with 28 places to the right
Decimal Decimal
of the decimal;
smallest nonzero number is +/-
0.0000000000000000000000000001 (+/-1E-28)

The City School /Academics/Computing Curriculum/Class 8/2020-2021 Page 47 of 75