how to visible text box?

i have a radio button and a text box. when i select the radio button, then will show out a text box to let user fill in. may i know to show the text box?
below are my coding.
   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TextBox2.Visible = True

        If RadioButton4.Checked = True Then
            TextBox2.Visible = True
        Else
            TextBox2.Visible = False
        End If


    End Sub
End Class

 hope someone can help me.