Public Function Zuordnung_Treeview_IndexLayoutfelder(ByVal TreeKey As String) _
  As integer()
  dim iArr() as integer, i as integer
  Dim bs As BindingSource                                'Erzeugen eines 
  ' Bindingsource-Objekt (bs) 
  bs = New BindingSource(DT_Lay, Nothing)                'mit der DataTable ( 
  ' DT_Lay) verbunden
  bs.Filter = ("NodeKey = '" & TreeKey & "'")            'Im BindingSourc kann 
  ' man nun filtern 
  bs.Sort = "LFDObjNr ASC"                               'die gewünschte 
  ' Sortierung eingeben
  Dim Anz As Integer = bs.Count                           'Anzahl der 
  ' gefundenen Rows
 
   For i = 0 To bs.Count - 1
       Dim st As String = CType(bs.Item(i), DataRowView).Row.Item( _
         "LFDObjNr").ToString
       ReDim Preserve iArr(i)
       iArr(i) = CInt(st)
   Next   
   return iArr
end sub

Public Sub LayDataSet_erstellen()
DT_Lay = DS_Lay.Tables.Add("Lay")
With DT_Lay
  .Columns.Add("LFDObjNr", GetType(Integer))     'Laufende Objektnummer 
  .Columns.Add("ObjVor", GetType(Boolean))
  .Columns.Add("ObjKey", GetType(String))        'ObjektKey - zum Erkennen des 
  ' Objektes 
  .Columns.Add("NodeKey", GetType(String))    
...
end With
end sub

Public Sub LayDataSet_befuellen(byval ObjName as string, byval ObjNr as integer)    
 Dim DR_Lay As DataRow
 Dim i As Integer = DT_Lay.Rows.Count
 
 If i = 0 Then ErstDataRow_Anlegen() : i = 1
   DR_Lay = DT_Lay.NewRow
   DR_Lay("LFDObjNr") = i
   DR_Lay("ObjVor") = True
   DR_Lay("ObjName") = ObjName
   DR_Lay("ObjNr") = ObjNr
   DR_Lay("NodeKey") = fLay.pr_TreeviewKey
   DT_Lay.Rows.Add(DR_Lay)
end sub