Lesson 4: Writing the Code in VB6

Welcome to Lesson 4 of our Visual Basic 6 Tutorial! In this lesson, you'll learn how to write effective VB6 program code to create interactive applications. We'll cover event procedures, control properties, calculations, and more with practical examples you can implement.

4.1 Introduction to Writing Code in Visual Basic

Each control or object in VB6 can initiate various events. These events are neatly cataloged in the dropdown menu within the code window. To unlock this menu, double-click on an object and pick your preferred event from the procedures' box.

4.2 Accessing the Code Window

To start writing code for an event procedure, double-click an object to enter the VB code window. For example, if you want to write code for the event of clicking a command button, double-click the command button and enter the codes in the event procedure.

4.3 Structure of an Event Procedure

The structure of an event procedure follows this pattern:

Private Sub Command1_Click()
    ' VB Statements
End Sub

4.4 Writing VB Statements

You enter the codes in the space between Private Sub Command1_Click and End Sub. The keyword Sub stands for a sub procedure that makes up part of all procedures in a program or module.

4.5 Understanding Object Properties

The syntax to set the property of an object or to pass a certain value to it is:

Object.Property

Where Object and Property are separated by a period. For example:

4.6 Examples of Event Procedures

Example 4.1: Changing Label Visibility and Text

Private Sub Command1_Click()
    Label1.Visible = False
    Label2.Visible = True
    Text1.Text = "You are correct!"
End Sub

Example 4.2: Updating a Label and Image

Private Sub Command1_Click()
    Label1.Caption = "Welcome"
    Image1.Visible = True
End Sub

Example 4.3: Showing Picture Box and Starting Timer

Private Sub Command1_Click()
    Picture1.Visible = True
    Timer1.Enabled = True
    Label1.Caption = "Start Counting"
End Sub

Example 4.4: Building a Counter

This counter starts counting after the user clicks the command button. We use a label as a counter, two command buttons, and a Timer control.

Dim n As Integer

Private Sub cmd_StartCount_Click()
    Timer1.Enabled = True
End Sub

Private Sub cmd_Stop_Click()
    Timer1.Enabled = False
End Sub

Private Sub cmd_Reset_Click()
    Lbl_Display.Caption = 0
    n = 0
End Sub

Private Sub Timer1_Timer()
    n = n + 1
    Lbl_Display.Caption = n
End Sub

Example 4.5: Click and Double Click Events

This program displays a message indicating whether a label was clicked once or twice.

Private Sub MyLabel_Click()
    MyLabel.Caption = "You Click Me Once"
End Sub

Private Sub MyLabel_DblClick()
    MyLabel.Caption = "You Click Me Twice!"
End Sub

Performing Calculations in Visual Basic

Program code that involves calculations is fairly easy to write, similar to mathematics. However, you need to know the basic arithmetic operators in VB:

Example: Type Conversion with Val Function

Private Sub Form_Activate()
    Text3.Text = Text1.Text + Text2.Text
End Sub

Private Sub Form_Activate()
    Text3.Text = Val(Text1.Text) + Val(Text2.Text)
End Sub

Next Lesson

Continue your VB6 journey with Lesson 5: VB Data Types.

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