VB Snippet - Create File Association

[James Stanich]

'Make a new project. Add a module. To the form add a command button. 
 
'Code:
'Add this code to the module:
 
Option Explicit
 
Public Const REG_SZ As Long = 1
Public Const REG_DWORD As Long = 4
Public Const HKEY_CLASSES_ROOT = &H80000000
Public Const HKEY_CURRENT_USER = &H80000001
Public Const HKEY_LOCAL_MACHINE = &H80000002
Public Const HKEY_USERS = &H80000003
 
Public Const ERROR_NONE = 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 ERROR_INVALID_PARAMETERS = 87
Public Const ERROR_NO_MORE_ITEMS = 259
 
Public Const KEY_ALL_ACCESS = &H3F
Public Const REG_OPTION_NON_VOLATILE = 0
 
Public Declare Function RegCloseKey Lib "advapi32.dll" _
   (ByVal hKey As Long) As Long
 
Public Declare Function RegCreateKeyEx _
    Lib "advapi32.dll" Alias "RegCreateKeyExA" _
   (ByVal hKey As Long, _
    ByVal lpSubKey As String, _
    ByVal Reserved As Long, _
    ByVal lpClass As String, _
    ByVal dwOptions As Long, _
    ByVal samDesired As Long, _
    ByVal lpSecurityAttributes As Long, _
    phkResult As Long, _
    lpdwDisposition As Long) As Long
 
Public Declare Function RegOpenKeyEx _
    Lib "advapi32.dll" Alias "RegOpenKeyExA" _
   (ByVal hKey As Long, _
    ByVal lpSubKey As String, _
    ByVal ulOptions As Long, _
    ByVal samDesired As Long, _
    phkResult As Long) As Long
 
Public Declare Function RegSetValueExString _
    Lib "advapi32.dll" Alias "RegSetValueExA" _
   (ByVal hKey As Long, _
    ByVal lpValueName As String, _
    ByVal Reserved As Long, _
    ByVal dwType As Long, _
    ByVal lpValue As String, _
    ByVal cbData As Long) As Long
 
Public Declare Function RegSetValueExLong _
   Lib "advapi32.dll" Alias "RegSetValueExA" _
  (ByVal hKey As Long, _
   ByVal lpValueName As String, _
   ByVal Reserved As Long, _
   ByVal dwType As Long, _
   lpValue As Long, _
   ByVal cbData As Long) As Long
 
 
Public Sub CreateAssociation()
 
   Dim sPath As String
   
  'File Associations begin with a listing
  'of the default extension under HKEY_CLASSES_ROOT.
  'So the first step is to create that
  'root extension item
   CreateNewKey ".xxx", HKEY_CLASSES_ROOT
   
   
  'To the extension just added, add a
  'subitem where the registry will look for
  'commands relating to the .xxx extension
  '("MyApp.Document"). Its type is String (REG_SZ)
   SetKeyValue ".xxx", "", "MyApp.Document", REG_SZ
   
   
  'Create the 'MyApp.Document' item under
  'HKEY_CLASSES_ROOT. This is where you'll put
  'the command line to execute or other shell
  'statements necessary.
   CreateNewKey "MyApp.Document\shell\open\command", HKEY_CLASSES_ROOT
   
   
  'Set its default item to "MyApp Document".
  'This is what is displayed in Explorer against
  'for files with a xxx extension. Its type is
  'String (REG_SZ)
   SetKeyValue "MyApp.Document", "", "MyApp Document", REG_SZ
   
   
  'Finally, add the path to myapp.exe
  'Remember to add %1 as the final command
  'parameter to assure the app opens the passed
  'command line item.
  '(results in '"c:\LongPathname\Myapp.exe %1")
  'Again, its type is string.
   sPath = "c:\LongPathname\Myapp.exe %1"
   SetKeyValue "MyApp.Document\shell\open\command", "", sPath, REG_SZ
   
  'All done
   MsgBox "The file association has been made!"
   
End Sub
 
 
Public Function SetValueEx(ByVal hKey As Long, _
                           sValueName As String, _
                           lType As Long, _
                           vValue As Variant) As Long
 
   Dim nValue As Long
   Dim sValue As String
   
   Select Case lType
      Case REG_SZ
         sValue = vValue & Chr$(0)
         SetValueEx = RegSetValueExString(hKey, _
                                          sValueName, _
                                          0&, _
                                          lType, _
                                          sValue, _
                                          Len(sValue))
         
      Case REG_DWORD
         nValue = vValue
         SetValueEx = RegSetValueExLong(hKey, _
                                        sValueName, _
                                        0&, _
                                        lType, _
                                        nValue, _
                                        4)
   
   End Select
   
End Function
 
 
Public Sub CreateNewKey(sNewKeyName As String, _
                        lPredefinedKey As Long)
 
  'handle to the new key
   Dim hKey As Long
  
  'result of the RegCreateKeyEx function
   Dim r As Long
   
   r = RegCreateKeyEx(lPredefinedKey, _
                      sNewKeyName, 0&, _
                      vbNullString, _
                      REG_OPTION_NON_VOLATILE, _
                      KEY_ALL_ACCESS, 0&, hKey, r)
   
   Call RegCloseKey(hKey)
 
End Sub
 
 
Public Sub SetKeyValue(sKeyName As String, _
                       sValueName As String, _
                       vValueSetting As Variant, _
                       lValueType As Long)
 
  'result of the SetValueEx function
   Dim r As Long
   
  'handle of opened key
   Dim hKey As Long
   
  'open the specified key
   r = RegOpenKeyEx(HKEY_CLASSES_ROOT, _
                    sKeyName, 0, _
                    KEY_ALL_ACCESS, hKey)
                    
   r = SetValueEx(hKey, _
                  sValueName, _
                  lValueType, _
                  vValueSetting)
                  
   Call RegCloseKey(hKey)
 
End Sub
 
'Add this code to the command button:
 
Private Sub Command1_Click()
 
CreateAssociation
 
End Sub