VB中使用系统注册表
ini文件大多用来寸放自己界面或者初始化信息，而应用程序要使用系统信息或者说要得知已在系统注册过的其他程序的一些信息就要读去系统注册表了，比如有些应用需要使用调用MS OutLook Express就需要从HKEY_LOCAL_MACHINE\Software\Microsoft\Outlook Express\中的InstallRoot中读取路径。
申明部分：
Option Explicit
Public Const READ_CONTROL = &H20000
Public Const STANDARD_RIGHTS_READ = (READ_CONTROL)
Public Const STANDARD_RIGHTS_WRITE = (READ_CONTROL)
Public Const KEY_QUERY_VALUE = &H1
Public Const KEY_SET_VALUE = &H2
Public Const KEY_CREATE_SUB_KEY = &H4
Public Const KEY_ENUMERATE_SUB_KEYS = &H8
Public Const KEY_NOTIFY = &H10
Public Const KEY_CREATE_LINK = &H20
Public Const SYNCHRONIZE = &H100000
Public Const STANDARD_RIGHTS_ALL = &H1F0000
Public Const KEY_READ = ((STANDARD_RIGHTS_READ Or KEY_QUERY_VALUE Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY) And (Not SYNCHRONIZE))
Public Const KEY_WRITE = ((STANDARD_RIGHTS_WRITE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY) And (Not SYNCHRONIZE))
Public Const KEY_ALL_ACCESS = ((STANDARD_RIGHTS_ALL Or KEY_QUERY_VALUE Or KEY_SET_VALUE Or KEY_CREATE_SUB_KEY Or KEY_ENUMERATE_SUB_KEYS Or KEY_NOTIFY Or KEY_CREATE_LINK) And (Not SYNCHRONIZE))
Public Const KEY_EXECUTE = ((KEY_READ) And (Not SYNCHRONIZE))
Public Const ERROR_SUCCESS = 0&
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
Declare Function RegQueryValueEx Lib "advapi32.dll" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, lpType As Long, lpData As Any, lpcbData As Long) As Long
Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Function sdaGetRegEntry(strKey As String, strSubKeys As String, strValName As String, lngType As Long) As String
On Error GoTo sdaGetRegEntry_Err
Dim lngResult As Long, lngKey As Long
Dim lngHandle As Long, lngcbData As Long
Dim strRet As String
Select Case strKey
Case "HKEY_CLASSES_ROOT": lngKey = &H80000000
Case "HKEY_CURRENT_CONFIG": lngKey = &H80000005
Case "HKEY_CURRENT_USER": lngKey = &H80000001
Case "HKEY_DYN_DATA": lngKey = &H80000006
Case "HKEY_LOCAL_MACHINE": lngKey = &H80000002
Case "HKEY_PERFORMANCE_DATA": lngKey = &H80000004
Case "HKEY_USERS": lngKey = &H80000003
Case Else: Exit Function
End Select
If Not ERROR_SUCCESS = RegOpenKeyEx(lngKey, strSubKeys, 0&, KEY_READ, lngHandle) Then Exit Function
lngResult = RegQueryValueEx(lngHandle, strValName, 0&, lngType, ByVal strRet, lngcbData)
strRet = Space(lngcbData)
lngResult = RegQueryValueEx(lngHandle, strValName, 0&, lngType, ByVal strRet, lngcbData)
If Not ERROR_SUCCESS = RegCloseKey(lngHandle) Then lngType = -1&
sdaGetRegEntry = strRet
sdaGetRegEntry_Exit:
On Error GoTo 0
Exit Function
sdaGetRegEntry_Err:
lngType = -1&
MsgBox Err & "> " & Error$, 16, "GenUtils/sdaGetRegEntry"
Resume sdaGetRegEntry_Exit
End Function
看起来很复杂，用起来却简单的紧，这就达到了复杂的目的了。
例如：使用OutLook Express
Dim outLook_Path As String
Dim shstring As String
outLook_Path = sdaGetRegEntry("HKEY_LOCAL_MACHINE", "Software\MicroSoft\Outlook Express\", "InstallRoot", 2)
shstring = Mid(Trim(outLook_Path), 1, Len(outLook_Path) - 1) & "\msimn.exe"
Shell shstring
