' Return codes from Registration functions.
Public Const ERROR_SUCCESS = 0&
Public Const ERROR_BADDB = 1&
Public Const ERROR_BADKEY = 2&
Public Const ERROR_CANTOPEN = 3&
Public Const ERROR_CANTREAD = 4&
Public Const ERROR_CANTWRITE = 5&
Public Const ERROR_OUTOFMEMORY = 6&
Public Const ERROR_INVALID_PARAMETER = 7&
Public Const ERROR_ACCESS_DENIED = 8&

Public Const HKEY_CLASSES_ROOT = &H80000000
Public Const MAX_PATH = 260&
Public Const REG_SZ = 1

          Dim sKeyName As String   'Holds Key Name in registry.
          Dim sKeyValue As String  'Holds Key Value in registry.
          Dim ret&        & ;nbs p;  'Holds error status if any from API calls.
          Dim lphKey&        'Holds created key handle from RegCreateKey.

      'This creates a Root entry called "MyApp".
          sKeyName = "MyApp"
          sKeyValue = "My Application"
          ret& = RegCreateKey&(HKEY_CLASSES_ROOT, sKeyName, lphKey&)
          ret& = RegSetValue&(lphKey&, "", REG_SZ, sKeyValue, 0&)

      'This creates a Root entry called .XXX associated with "MyApp".
      'You can replace ".XXX" with your wanted extension
          sKeyName = ".XXX"
      'replace all "MyApp" below with your application name
          sKeyValue = "MyApp"
          ret& = RegCreateKey&(HKEY_CLASSES_ROOT, sKeyName, lphKey&)
          ret& = RegSetValue&(lphKey&, "", REG_SZ, sKeyValue, 0&)

      'This sets the command line for "MyApp".
          sKeyName = "MyApp"
      'replace c:\mydir\my.exe with your exe file. In this example,
      'All the .XXX files will be opened with the file c:\mydir\my.exe
          sKeyValue = "c:\mydir\my.exe %1"
          ret& = RegCreateKey&(HKEY_CLASSES_ROOT, sKeyName, lphKey&)
          ret& = RegSetValue&(lphKey&, "shell\open\command", REG_SZ, _
                                   sKeyValue, MAX_PATH)

End Sub