enumerate?

[Cyber-Drugs]

I'm trying to use a class that a friend wrote for me, but he's not had much time ot help me out but has explained to me that I need to, in his own words:

"To read the information you can enumerate through the GenericTree using its IEnumerable interface"

I have no clue what that means, so that's where I need your help...

Here is the code for the class:

Imports System
 
Namespace QuestionTree
  Public MustInherit Class HierarchyElement
    Private _id As Integer
    Private name as String
 
    Public ReadOnly Property Name() As String
      Get
        Return _name
      End Get
    End Property
 
    Public ReadOnly Property Id() As Integer
      Get
      End Get
    End Property
 
    Protected Sub New(ByVal _name As String, ByVal _id As Integer)
      Me._name = _name
      Me._id = _id
    End Sub
  End Class
 
  Public Class SectionElement
    Inherits HierachyElement
 
    Public Sub New(ByVal _name As String, ByVal _id As Integer)
      MyBase.New(_name, _id)
    End Sub
  End Class
 
  Public Class SubsectionElement
    Inherits HierachyElement
 
    Public Sub New(ByVal _name As String, ByVal _id As Integer)
      MyBase.New(_name, _id)
    End Sub
  End Class
 
  Public Class QuestionElement
    Inherits HierachyElement
 
    Public Enum AnswerType
      ANSWER_TYPE_CHECKBOX
      ANSWER_TYPE_RADIO
    End Enum
 
    Private _answerType As AnswerType
    Private [_text] As String
    Private answered As Boolean
 
    Public Sub New(ByVal [_text] As String, ByVal _id As Integer, ByVal _answerType As AnswerType)
      MyBase.New("question", _id)
      Me._text = [_text]
      Me._answerType = _answerType
    End Sub
 
    Public ReadOnly Property [Text]() As String
      Get
        Return [_text]
      End Get
    End Property
 
    Public Property Answered() As Boolean
      Get
        Return _answered
      End Get
      Set(ByVal Value As Boolean)
        _answered = Value
      End Set
    End Property
  End Class
End Namespace

Anyone able to help me out?