C++

  int ShowAllHiddenObjects( CRhinoDoc& doc, bool bRedraw )
  {
    CRhinoObjectIterator it(
          doc,
          CRhinoObjectIterator::undeleted_objects,
          CRhinoObjectIterator::active_and_reference_objects
          );
    it.IncludeLights();


    int count = 0;
    CRhinoObject* obj = 0;
    for( obj = it.First(); obj; obj = it.Next() )
    {
      // Ignore objects that are not hidden
      if( obj->Attributes().Mode() != ON::hidden_object )
        continue;
      // Ignore objects on hidden or locked layers
      if( ON::normal_layer != obj->ObjectLayer().Mode() )
        continue;
      if( doc.ShowObject(obj) )
        count++;
    }


    if( count > 0 && bRedraw )
      doc.Redraw();
    return count;
  }

VB.NET (Rhino 4)

  Public Overrides Function RunCommand(ByVal context As IRhinoCommandContext) _
    As RMA.Rhino.IRhinoCommand.result


    Dim it As New MRhinoObjectIterator( _
            IRhinoObjectIterator.object_state.undeleted_objects, _
            IRhinoObjectIterator.object_category.active_and_reference_objects)
    it.IncludeLights()
    Dim count As Integer = 0


    For Each obj As MRhinoObject In it
      ' Ignore objects that are not hidden
      If (obj.Attributes().Mode() <> IOn.object_mode.hidden_object) Then
        Continue For
      End If
      ' Ignore objects on hidden or locked layers
      If (obj.ObjectLayer().IsVisibleAndNotLocked()) Then
        Dim obj_ref As New MRhinoObjRef(obj)
        If (context.m_doc.ShowObject(obj_ref)) Then
          count = count + 1
        End If
      End If
    Next
    If (count > 0) Then context.m_doc.Redraw()
    Return IRhinoCommand.result.success
  End Function

C# (Rhino 4)

  public override IRhinoCommand.result RunCommand(IRhinoCommandContext context)
  {
    MRhinoObjectIterator it =
      new MRhinoObjectIterator( 
          IRhinoObjectIterator.object_state.undeleted_objects,
          IRhinoObjectIterator.object_category.active_and_reference_objects);
    it.IncludeLights();
    int count = 0;


    foreach( MRhinoObject obj in it )
    {
      // Ignore objects that are not hidden
      if(obj.Attributes().Mode() != IOn.object_mode.hidden_object)
        continue;
      // Ignore objects on hidden or locked layers
      if(obj.ObjectLayer().IsVisibleAndNotLocked())
      {
        MRhinoObjRef obj_ref = new MRhinoObjRef(obj);
        if(context.m_doc.ShowObject(obj_ref))
          count++;
      }
    }
    if (count > 0)
      context.m_doc.Redraw();
    return IRhinoCommand.result.success;
  }