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The radio button is also a very useful control in
Visual Basic 2010. 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 out of
a number of choices. Here is an example which allows the user to
select one color only.
Example 18.1
The Code:
Dim strColor As String
Private Sub
RadioButton8_CheckedChanged(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles
RadioButton8.CheckedChanged
strColor = "Red"
End
Sub
Private Sub RadioButton7_CheckedChanged(ByVal sender
As System.Object, ByVal e As System.EventArgs) Handles
RadioButton7.CheckedChanged
strColor = "Green"
End
Sub
Private Sub RadioYellow_CheckedChanged(ByVal sender
As System.Object, ByVal e As System.EventArgs) Handles
RadioYellow.CheckedChanged
strColor = "Yellow"
End
Sub
Private Sub Button1_Click(ByVal sender As
System.Object, ByVal e As System.EventArgs) Handles
Button1.Click
Label2.Text = strColor
End
Sub
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
VB2010 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.
Example 18.2
The code:
Dim
strColor As String
Dim strSize As String
Private Sub
RadioButton8_CheckedChanged(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles RadioButton8.CheckedChanged
strColor
= "Red"
End Sub
Private Sub
RadioButton7_CheckedChanged(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles RadioButton7.CheckedChanged
strColor
= "Green"
End Sub
Private Sub
RadioYellow_CheckedChanged(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles RadioYellow.CheckedChanged
strColor =
"Yellow"
End Sub
Private Sub Button1_Click(ByVal sender As
System.Object, ByVal e As System.EventArgs) Handles
Button1.Click
Label2.Text = strColor
Label4.Text =
strSize
End Sub
Private Sub
RadioXL_CheckedChanged(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles RadioXL.CheckedChanged
strSize =
"XL"
End Sub
Private Sub RadioL_CheckedChanged(ByVal
sender As System.Object, ByVal e As System.EventArgs) Handles
RadioL.CheckedChanged
strSize = "L"
End Sub
Private Sub
RadioM_CheckedChanged(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles RadioM.CheckedChanged
strSize =
"M"
End Sub
Private Sub RadioS_CheckedChanged(ByVal sender
As System.Object, ByVal e As System.EventArgs) Handles
RadioS.CheckedChanged
strSize = "S"
End
Sub
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