control vb2008

Controls  in VB2008 are useful tools that can be placed in the form to perform various tasks. They are used to create many kinds of Windows applications. The diagram on the right is the Toolbox that contains the  controls of VB2008. They are categorized into Common Controls, Containers, Menus, Toolbars, Data, Components, Printings and Dialogs. At the moment, we will focus on the common controls. Some of the most used common controls are Button, Label, ComboBox, ListBox, PictureBox, TextBox etc. To insert a control into your form, you just need to drag the control and drop it into the form. You can reposition and resize it  as you like. Let's examine a few programs that made use of  Button, Label, TextBox , ListBox and PictureBox . You don't have to worry so much about the code because we will explain the program syntax as you progress to later lessons.

2.1 Using Text Box-A multiplication program

In this program, you insert two textboxes , three labels and one button. The two textboxes are for the users to enter two numbers, one label is to display the multiplication operator and the other label is to display the equal sign. The last label is to display the answer.

The Code Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim num1, num2, product As Single num1 = TextBox1.Text num2 = TextBox2.Text product = num1 * num2 Label3.Text = product End Sub

2.2 Using the ListBox-A program to add items to a list box

This program will add one item at a time as the user enter an item into the TextBox and click the Add button.

The code

Class Frm1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim item As String
item = TextBox1.Text

'To add items to a listbox
ListBox1.Items.Add(item)
End Sub
End Class

　

2.3 Using the PictureBox

In this program, we insert a PictureBox and a Button into the form. Make sure to set the SizeMode property of the PictureBox to StretchImage so that the whole picture can be viewed in the picture box. Key in the code as shown below and you can load an image from a certain image file into the PictureBox.

The Code

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'To load an image into the PictureBox from an image file
PictureBox1.Image = Image.FromFile("c:\Users\Public\Pictures\Sample Pictures\Frangipani Flowers.jpg")
End Sub