Private Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" ( _
  ByVal HKEY As Long, ByVal lpSubKey As String, phkResult As Long) As Long
Private Declare Function RegQueryValueEx Lib "advapi32.dll" Alias _
"RegQueryValueExA" (ByVal HKEY As Long, ByVal lpValueName As String, ByVal _
lpReserved As Long, lpType As Long, lpData As Any, lpcbData As Long) As Long
Private Declare Function RegSetValueEx Lib "advapi32.dll" Alias _
"RegSetValueExA" (ByVal HKEY As Long, ByVal lpValueName As String, ByVal _
Reserved As Long, ByVal dwType As Long, lpData As Any, ByVal cbData As Long) As _
Long
Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal HKEY As Long) As _
Long
Private Declare Function RegCreateKey Lib "advapi32.dll" Alias "RegCreateKeyA" ( _
ByVal HKEY As Long, ByVal lpSubKey As String, phkResult As Long) As Long
 
Public Enum HKEY
  HKEY_CLASSES_ROOT = &H80000000
  HKEY_CURRENT_USER = &H80000001
  HKEY_LOCAL_MACHINE = &H80000002
  HKEY_USERS = &H80000002
  HKEY_CURRENT_CONFIG = &H80000002
End Enum
 
Public Type FileIconString
  IconsPath As String
  IconIndex As Long
End Type
 
Private Const REG_SZ = 1
Private Const REG_EXPAND_SZ = 2
Private Const REG_BINARY = 3
 
Public Function fStringSpeichern(H_KEY As HKEY, sPath As String, sValue As _
  String, iData As String)
 
  Dim vRet As Variant
 
  RegCreateKey H_KEY, sPath, vRet
  RegSetValueEx vRet, sValue, 0, REG_SZ, ByVal iData, Len(iData)
  RegCloseKey vRet
End Function
 
Public Function fWertLesen(H_KEY As HKEY, sPath As String, sValue As String)
  Dim vRet As Variant
 
  RegOpenKey H_KEY, sPath, vRet
  fWertLesen = fRegAbfrageWert(vRet, sValue)
  RegCloseKey vRet
End Function
 
Private Function fRegAbfrageWert(ByVal H_KEY As Long, ByVal sValueName As _
  String) As String
 
  Dim sBuffer As String
  Dim lRes As Long
  Dim lTypeValue As Long
  Dim lBufferSizeData As Long
  Dim iData As Integer
 
  lRes = RegQueryValueEx(H_KEY, sValueName, 0, _
    lTypeValue, ByVal 0, lBufferSizeData)
  If lRes = 0 Then
    If lTypeValue = REG_SZ Or 2 Then
      sBuffer = String(lBufferSizeData, Chr$(0))
      lRes = RegQueryValueEx(H_KEY, sValueName, 0, _
        0, ByVal sBuffer, lBufferSizeData)
      If lRes = 0 Then
        fRegAbfrageWert = Left$(sBuffer, _
          InStr(1, sBuffer, Chr$(0)) - 1)
      End If
    ElseIf lTypeValue = REG_BINARY Then
      lRes = RegQueryValueEx(H_KEY, sValueName, 0, _
        0, iData, lBufferSizeData)
      If lRes = 0 Then
        fRegAbfrageWert = iData
      End If
    End If
  End If
End Function

Dim Zwichenergebnis as string
Zwichenergebnis=fWertLesen(HKEY_CLASSES_ROOT, ".txt", "")
Zwichenergebnis = fWertLesen(HKEY_CLASSES_ROOT, Zwichenergebnis & _
  "\DefaultIcon", "")