This VB example initializes a combo box with MAC addresses and uses it to switch between the cameras:
Private Sub Form_Load()
CamMACLst = ActiveGige1.GetCameraMACList
For i = 0 ToUBound(CamMACLst)
Combo1.AddItem (CamMACLst(i))
Next
Combo1.ListIndex = 0
ActiveGige1.Acquire = True
End Sub
Private Sub Combo1_Click()
ActiveGige1.Camera = Combo1.ListIndex
End Sub
This MFC example fills out a combo box with MAC addresses: