How to Write a Subroutine in VB.net

Subroutines give you the ability to write code that can be used over and over again in a program. This saves you time from writing the same code more than once. In this example I am writing a subroutine that will sort some numbers.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• VB.net
• basic programming skills

1. Open VB.net

2. Create a new project

3. 
   Sort Button

   Place a button on the form and change its text property to "Sort".

4. 
   Listbox

   Place a listbox on the form. This is where we will display the sorted list.

5. 
   Click Event

   Double click on the button control to bring up the code window and the button's click event.

6. 
   Global Variable

   Directly above the click event subroutine type in:
   Public aryNumberList(5) As Integer
   
   This creates our public global variable array that we will use in our example to hold our numbers.

7. 
   Loop variable

   In the button's click event delcare a loop variable. This will be used to add our array items after they have been sorted the our listbox.

8. 
   Assign numbers

   Add numbers in a random order to our array variable that we declared in step 6.

9. 
   Subroutine

   Before we do anything else we must now create our sorting subroutine. Remember this is just an example so to keep it simple I am using a basic swapping sort. You can see the code in the picture.

10. 
    Call Subroutine

    Go back into the click event and call the subroutine passing the global array variable as a parameter.

11. 
    Display the sorted list

    Display the sorted list in the listbox.

12. Press the "F5" key on your keyboard to run the application.

13. Click the sort button.

14. 
    Final Results

    Your listbox should now display the numbers in their proper order.

Resources

• Mike's How-To Blog