How to use RegDeleteValue

[BobRodes]

I'm having a hard time figuring out RegDeleteValue. I have a registry key: HKEY_LOCAL_MACHINE\SOFTWARE\MyCompany\MyApp\MySubKey

I would like to remove certain values from this folder location, while preserving others. So, let's say I have a value whose name is "SQLDataSource" and whose value is "MYSERVER".

The code line
RegDeleteValue (HKEY_LOCAL_MACHINE, "SOFTWARE\MyCompany\MyApp\MySubKey\SQLDataSource&quot fails. I've tried several other things, and any doc or examples that I've found are very vague about what the second argument needs to be. For example, is a "registry value" the name or the data?

Can someone enlighten me?

Thanks,

Bob

 

[vb5prgrmr]

You first have to open the registry and retrieve a key to the value you want to modify. Look at RegOpenKeyEx API (Also you may have to close the key).

Good Luck

 

[tsuji]

Hello BobRodes,

[1] The parameters fed into RegDeleteValue API
Declare Function RegDeleteValue Lib "advapi32.dll" _
Alias "RegDeleteValueA" ( _
ByVal hKey As Long, _
ByVal lpValueName As String) As Long
are actually
[1.1] hKey As Long : being the handle of your targetted registry Key
"HKEY_LOCAL_MACHINE\SOFTWARE\MyCompany\MyApp\MySubKey"
(As a handle of long, you should not expect it be the key string itself.)
[1.2] lpValueName As String : being the value name itself, so it be "SQLDataSource"

[3] Now the hKey is returned when you Open the key by the API function
[3.1] 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
[3.2] where the return by reference phkResult is fed into the hKey of [1].
[3.3] The hKey here is the root key constant &H80000002 for HKEY_LOCAL_MACHINE.
In practical terms, the function's return RegOpenKeyEx provides a test of the existence of the key itself =0& means successful/existing of the key.

[4] Once the open is successful (returning 0&), call the RegDeleteValue by feeding the so-obtained phkResult ([3.2]) and lpValueName ([1.2]), the deletion of value would be successful if RegDeleteValue returns True. If it returns False, the probable reason is the non-existence of the value name at all.

[5] If all the hundles are over, you have to call the API
[5.1] Declare Function RegCloseKey Lib "advapi32.dll" _
(ByVal hKey As Long) As Long
[5.2] Here hKey is again the handle of the key "HKEY_...\...\SubKey", ie that from [3.2]

This is the complete rundown of the construction of this functionality. Hope you get the idea.

regards - tsuji

 

[BobRodes]

Thanks so much for your detailed replay, tsuji. Sorry not to have responded for so long; I've been out of commission with a bad motherboard.

Bob