Keep a layer visible with ArcObjects VBA

Summary

The code sample provided can be used to keep the top layer turned on. It is possible to customize it to work with another layer. This essentially disables turning off the layer.

Procedure

1. Start ArcMap.
2. Open the Visual Basic Editor.
   
   
   In ArcMap, select Tools > Macros > Visual Basic Editor.
   
   
3. In the Project Explorer window, expand Project and select ArcMap Objects > ThisDocument then right-click and select View Code.
   
   
   

   Note:
   Code in the Project's ThisDocument code module will only run in the current map document.  If you want to store the code in all your map documents open the Normal.mxt ThisDocument code module instead.

   
   
4. Copy the following code into the code module.
   

   Code:
   Dim m_pMxDoc As IMxDocument
   Dim m_pMap As IMap
   Dim m_pLayer As ILayer
   Dim WithEvents m_pLyrEvents As FeatureLayer
   Private WithEvents m_pActiveViewEvents As Map
   
   Private Function MxDocument_OpenDocument() As Boolean
       Set m_pMxDoc = Application.Document
       Set m_pMap = m_pMxDoc.FocusMap
       Set m_pLyrEvents = m_pMap.Layer(0)  'change this number if you wish to work with a different layer
       Set m_pActiveViewEvents = m_pMxDoc.FocusMap
   End Function
   
   Private Sub m_pActiveViewEvents_ViewRefreshed(ByVal view As esriCarto.IActiveView, _
   ByVal phase As esriCarto.esriViewDrawPhase, ByVal data As Variant, ByVal envelope As esriGeometry.IEnvelope)
       Set m_pLayer = m_pLyrEvents
       m_pLayer.Visible = True
   End Sub
   
   Private Sub m_pLyrEvents_VisibilityChanged(ByVal currentState As Boolean)
       Set m_pLayer = m_pLyrEvents
       If currentState = False Then
           m_pLayer.Visible = True
           m_pMxDoc.UpdateContents
           Exit Sub
       Else
           Exit Sub
       End If
   End Sub
   
   Sub StopListening()
       Set m_pLyrEvents = Nothing
       Set m_pActiveViewEvents = Nothing
   End Sub
   

   
   
5. Close the Visual Basic Editor.
6. Save and close the ArcMap document.
7. Open the same ArcMap document.
8. Click the layer visibility checkbox for the top layer. You should see that it is rendered useless.