Option Explicit
 
Private m_cIndex As Collection
Private mCounter As Long        '** belegter Speicher
Private mMaxIndex As Long       '** aktuelle ArrayGröße
Private bChanged As Boolean     '** Index geändert?
 
Private Type Koordinaten_STRUC
  x As Long
  y As Long
  Counter As Long
  Key As String
End Type
 
Private Koordinaten() As Koordinaten_STRUC
 
Private Sub Class_Initialize()
  Set m_cIndex = New Collection
  mCounter = 0
  maxindex = 1000
  ReDim Preserve Koordinaten(1 To maxindex)
  Call ReadData
  bChanged = False
End Sub
 
Private Sub Class_Terminate()
  If bChanged Then Call SaveData
  Set m_cIndex = Nothing
End Sub
 
Sub Add(x As Long, y As Long)
 
  Dim sKey As String
  Dim iIndex As Long
 
  sKey = x & Chr$(0) & y
  iIndex = KeyExists(sKey)
 
  If iIndex = 0 Then
 
    '** NEUEINTRAG
 
    '** Index ermitteln und in Collection eintragen
    iIndex = m_cIndex.Count + 1
    m_cIndex.Add iIndex, sKey
 
    '** höchsten Index merken für Speicheranpassung
    mCounter = iIndex
 
    '** UDT Array anpassen
    If iIndex >= maxindex Then
      maxindex = 2 * maxindex
      ReDim Preserve Koordinaten(1 To maxindex)
    End If
 
    '** UDT eintragen
    With Koordinaten(iIndex)
      .x = x
      .y = y
      .Counter = 1
      .Key = sKey  '** nur zum Debuggen
    End With
 
  Else
    '** Eintrag vorhanden
    Koordinaten(iIndex).Counter = Koordinaten(iIndex).Counter + 1
  End If
 
  bChanged = True  '** Änderungen gemacht, also beim Beenden speichern
 
End Sub
 
Private Function KeyExists(sKey As String) As Long
  '** existiert der Schlüssel in der Collection
 
  On Error Resume Next
  KeyExists = m_cIndex(sKey)
  On Error GoTo 0
 
End Function
 
Private Sub ReadData()
  '** wenn Datei vorhanden, dann einlesen
  ...
End Sub
 
Private Sub SaveData()
  '** UDT in Datei schreiben
  ...
End Sub