Start a new application and name it Area. We are going to use scroll bars to select the width and length of a room. When a scroll changes, we will display the value in a label, then calculate the area from the values of the two scroll bars and display it. Later, we may want to add another scroll bar to select the cost of carpeting and calculate the cost to carpet the room.
Instead of writing all of the calculations for each scroll bar, we will use a general procedure all it from each of the scroll bar scroll events. One important reason to not repeat code is because it can lead to errors when the code needs to be updated.
Build the form as shown in the illustration, using labels 
(from top to bottom) LblInstructions, LblLength (text = 1), LblAreaHeader, LblArea, and LblWidth (text=1).
Add a vertical scroll bar 
VsbWidth: LargeChange=1, Minimum=1, and Value=1.
Add a horizontal scroll bar 
HsbLength: LargeChange=1, Minimum=1, and Value=1.
Write the code as shown below:
Private Sub Calc() 'a general procedure, not associated with any event
Dim Area As Integer
Area = Me.HsbLength.Value * Me.VsbWidth.Value
Me.LblArea.Text = Area
End Sub 'Calc
Private Sub HsbLength_Scroll(ByVal sender As System.Object, ByVal e As _
System.Windows.Forms.ScrollEventArgs) Handles HsbLength.Scroll
Me.LblLength.Text = Me.HsbLength.Value
Calc()
End Sub 'HsbLength_Scroll
Private Sub VsbWidth_Scroll(ByVal sender As System.Object, ByVal e _
As System.Windows.Forms.ScrollEventArgs) Handles VsbWidth.Scroll
Me.LblWidth.Text = Me.VsbWidth.Value
Calc()
End Sub 'VsbWidth_Scroll
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Calc() 'This is so the area will show correctly at start
End Sub 'Form1_Load
INDEX, General Procedures
Next lesson: Dialogs in Visual Basic
