Microsoft KB Archive/178755

= How To Enumerate the Values of a Registry Key =

Article ID: 178755

Article Last Modified on 3/11/2005

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APPLIES TO


 * Microsoft Visual Basic 5.0 Learning Edition
 * Microsoft Visual Basic 6.0 Learning Edition
 * Microsoft Visual Basic 5.0 Professional Edition
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 5.0 Enterprise Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition

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This article was previously published under Q178755



SUMMARY
The RegEnumValue function allows you to enumerate the values of a registry key. Program settings are commonly stored in the registry. Enumerating through a registry key enables you to read the registry settings of a program so that you can restore the settings the next time you start the program.

This article shows you how to use the RegEnumValue function to enumerate the values of a registry key.



MORE INFORMATION
The following is the Visual Basic declaration statement for RegEnumValue: Private Declare Function RegEnumValue Lib "advapi32.dll" _ Alias "RegEnumValueA" _ (ByVal hKey As Long, _                  ByVal dwIndex As Long, _                   ByVal lpValueName As String, _                   lpcbValueName As Long, _                   ByVal lpReserved As Long, _                   lpType As Long, _                   lpData As Any, _                   lpcbData As Long) As Long

NOTE: The function declaration listed in the API text viewer for the RegEnumValue function is incorrect. The fifth parameter, lpReserved, should be passed by value as illustrated above. For more information, please see the following article in the Microsoft Knowledge Base:

173009 PRB: Runtime Error 87 Using RegEnumValue Function

The next section illustrates how to create a sample project that displays the values of a specified registry key in a list box.

Step-by-Step Example
 Start a new Standard EXE project in Visual Basic. Form1 is created by default. Add a CommandButton and a ListBox control to Form1. Because many of the entries are lengthy, you should extend the ListBox across the full width of the form. The height of the ListBox should be several lines.  Paste the following code into the code window of Form1: Option Explicit

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 RegEnumValue Lib "advapi32.dll" _ Alias "RegEnumValueA" _ (ByVal hKey As Long, _         ByVal dwIndex As Long, _          ByVal lpValueName As String, _          lpcbValueName As Long, _          ByVal lpReserved As Long, _          lpType As Long, _          lpData As Any, _          lpcbData As Long) As Long

Private Declare Function RegCloseKey Lib "advapi32.dll" _ (ByVal hKey As Long) As Long

Const HKEY_CLASSES_ROOT = &H80000000 Const HKEY_CURRENT_USER = &H80000001 Const HKEY_LOCAL_MACHINE = &H80000002 Const HKEY_USERS = &H80000003

Const ERROR_SUCCESS = 0&

Const SYNCHRONIZE = &H100000 Const STANDARD_RIGHTS_READ = &H20000 Const STANDARD_RIGHTS_WRITE = &H20000 Const STANDARD_RIGHTS_EXECUTE = &H20000 Const STANDARD_RIGHTS_REQUIRED = &HF0000 Const STANDARD_RIGHTS_ALL = &H1F0000 Const KEY_QUERY_VALUE = &H1 Const KEY_SET_VALUE = &H2 Const KEY_CREATE_SUB_KEY = &H4 Const KEY_ENUMERATE_SUB_KEYS = &H8 Const KEY_NOTIFY = &H10 Const KEY_CREATE_LINK = &H20 Const KEY_READ = ((STANDARD_RIGHTS_READ Or _ KEY_QUERY_VALUE Or _ KEY_ENUMERATE_SUB_KEYS Or _ KEY_NOTIFY) And _                       (Not SYNCHRONIZE))

Const REG_DWORD = 4 Const REG_BINARY = 3 Const REG_SZ = 1

Private Sub Command1_Click Dim lngKeyHandle As Long Dim lngResult As Long Dim lngCurIdx As Long Dim strValue As String Dim lngValueLen As Long Dim lngData As Long Dim lngDataLen As Long Dim strResult As String

lngResult = RegOpenKeyEx(HKEY_LOCAL_MACHINE, _                "SOFTWARE\Microsoft\Windows\CurrentVersion\SharedDlls", _                  0&, _                  KEY_READ, _                  lngKeyHandle)

If lngResult <> ERROR_SUCCESS Then MsgBox "Cannot open key" Exit Sub End If

lngCurIdx = 0 Do           lngValueLen = 2000 strValue = String(lngValueLen, 0) lngDataLen = 2000

lngResult = RegEnumValue(lngKeyHandle, _                                    lngCurIdx, _                                     ByVal strValue, _                                     lngValueLen, _                                     0&, _                                     REG_DWORD, _                                     ByVal lngData, _                                     lngDataLen) lngCurIdx = lngCurIdx + 1

If lngResult = ERROR_SUCCESS Then strResult = lngCurIdx & ": " & Left(strValue, lngValueLen) List1.AddItem strResult End If

Loop While lngResult = ERROR_SUCCESS Call RegCloseKey(lngKeyHandle) End Sub  On the Start menu, click Run, or press the F5 key, to start the program. Click CommandButton. All the values for the following registry key appear in the list box:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\SharedDlls



