The radio button is also a very useful control in Visual Basic
2008. However, it operates differently from the check boxes. While the
checkboxes work independently and allows the user to select one or more items
, radio buttons are mutually exclusive, which means the user can only choose one
item only from a number of choices. Here is an example that allows the selection of one color only.
Dim strColor As String
Private Sub RadioButton8_CheckedChanged(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles RadioButton8.CheckedChanged
strColor = "Red"
Private Sub RadioButton7_CheckedChanged(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles RadioButton7.CheckedChanged
strColor = "Green"
Private Sub RadioYellow_CheckedChanged(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles RadioYellow.CheckedChanged
strColor = "Yellow"
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
Label2.Text = strColor
Although the user may only select one item at a time,
he may make more than one selection if those items belong to different
categories. For example, the user wish to choose T-shirt size and color, he
needs to select one color and one size, which means one selection in each
category. This is easily achieved in VB2008 by using the Groupbox control
under the containers categories. After inserting the Groupbox into the form, you
can proceed to insert the radio buttons into the Groupbox. Only the radio
buttons inside the Groupbox are mutually exclusive, they are not mutually
exclusive with the radio buttons outside the Groupbox. In Example 18.2, the
users can select one color and one size of the T-shirt.