© 2010 Autodesk
Introduction to Revit 2011 API
Element Filtering
2.1 List of Instances of a Specific Object Class - System Family
§Collect all the instances of wall
<VB.NET>
    Dim wallCollector = New FilteredElementCollector(m_rvtDoc).OfClass(GetType(Wall))
    Dim wallList As IList(Of Element) = wallCollector.ToElements
</VB.NET>