Public Class MyForm
  Inherits System.Windows.Forms.Form

  Dim UIControls(2) As Object

  Public Sub OnMouseClick(ByVal sender As Object, _
  ByVal e As EventArgs) Handles MyBase.Click
    Dim i As Integer

    For i = 0 To 2
      If CType(UIControls(i), IUIControl).IsPtInControl(MousePosition()) Then
        CType(UIControls(i), IUIControl).ControlPressed()
        CType(UIControls(i), IUIControl).Paint()
      End If
    Next
  End Sub
End Class