Registry key Exists [Resolved]

[MikkyThomeon]

I have searched the other posts but they do not work for this key:


HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MySQL Connector/ODBC 3.51


I have tried using this code:

Private 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
 
Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As _
    Long
    
Const KEY_READ = &H20019
Const HKEY_CLASSES_ROOT = &H80000000
Const HKEY_CURRENT_CONFIG = &H80000005
Const HKEY_CURRENT_USER = &H80000001
Const HKEY_LOCAL_MACHINE = &H80000002
Const HKEY_USERS = &H80000003
 
' Return True if a Registry key exists
 
Public Function CheckRegistryKey(ByVal hKey As Long, ByVal KeyName As String) As Boolean
    Dim handle As Long
    ' Try to open the key
    If RegOpenKeyEx(hKey, KeyName, 0, KEY_READ, handle) = 0 Then
        ' The key exists
        CheckRegistryKey = True
        ' Close it before exiting
        RegCloseKey handle
    End If
End Function

How can I check if the key actually exists???

[MikkyThomeon]

BTW:

Private Sub Form_Load()
    CheckRegistryKey HKEY_LOCAL_MACHINE, "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MySQL Connector/ODBC 3.51"
End Sub

... this is how I was colling the function. Is that OK??

[manavo11]

From the API-Guide regarding the RegOpenKeyEx :

If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in WINERROR.H. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error.

[BrianS]

Which means you need to check the RetVal

[BrianS]

If you like, I can upload a reall good Registry Demo project.

[MikkyThomeon]

Please Brian - I would be really grateful! Sorry I took a while. Went home to eat, shower and (sleep!!!) a bit before tackling this again.

I also checked out the API Guide and I am checking for Retval = 0

If RegOpenKeyEx(hKey, KeyName, 0, KEY_READ, handle) = 0 Then

The value for the constatnt ERROR_SUCCESS is zero

Public Const ERROR_SUCCESS = 0&

Thanks once again mate.

[BrianS]

Not sure if you can do that, but not sure. I normally use :

RetVal = RegOpenKeyEx(hKey, KeyName, 0, KEY_READ, handle)

But here is the Registry Project for you to check out.

[MikkyThomeon]

Thanks Brian. This issue is resolved with a simple solution!!!

'---------------------------------------------------------------------------------------
' Procedure : IsDriverInstalled
' DateTime  : 2004/02/25 12:48
' Author    : Administrator
' Purpose   : Checks if the uninstall key exists - this indicates that the
'             MyODBC driver has been installed on the target system
'---------------------------------------------------------------------------------------
'
Function IsMyODBCInstalled() As Boolean
    Dim hKey As Long
    If RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MySQL Connector/ODBC 3.51", 0, 1, hKey) = ERROR_SUCCESS Then
        IsMyODBCInstalled = True
        RegCloseKey hKey
    Else
        IsMyODBCInstalled = False
    End If
End Function