lpcbData As Long) As Long
-----------------------------------------------------------------------------
使用两个宣告来解决这个问题，依不同的lpType呼叫不同的函式，即lpType= REG_
DWORD时，呼叫RegQueryLong, lpType = REG_SZ时则为RegQueryString这也可以让我们
了解为何VB API的宣告为什麽要有Alias的存在。
范例三
*****************************************************************************
Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) _
As Long
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 RegQueryString Lib "advapi32.dll" Alias _
"RegQueryValueExA" (ByVal hKey As Long, _
ByVal lpValueName As String, ByVal lpReserved As Long, _
lpType As Long, ByVal lpData As String, lpcbData As Long) As Long
Const REG_EXPAND_SZ = 2
Const HKEY_CLASSES_ROOT = &H80000000
Const READ_CONTROL = &H20000
Const STANDARD_RIGHTS_READ = (READ_CONTROL)
Const KEY_QUERY_VALUE = &H1
Const KEY_ENUMERATE_SUB_KEYS = &H8
Const KEY_NOTIFY = &H10
Const SYNCHRONIZE = &H100000
Const KEY_READ = ((STANDARD_RIGHTS_READ Or _
KEY_QUERY_VALUE Or KEY_ENUMERATE_SUB_KEYS Or _
KEY_NOTIFY) And (Not SYNCHRONIZE))
Dim key5 As String, ValueName as String, strBuff as String, ResultStr as String
Dim leng1 As Long, resul As Long, hkey As Long
Dim tp As Long, i As Long
key5 = " SOFTWARE\Microsoft\Windows\CurrentVerson "
resul = RegOpenKeyEx(HKEY_CLASSES_ROOT, key5, 0, KEY_READ, hkey)
'hkey便是subkey (key5)的KeyHandle，先取得它才能存取Subkey内的ValueName
ValueName= "ProDuctId "
tp = REG_SZ
strBuff = String(255, 0)
leng1 = Len(strBuff) + 1
resul = RegQueryString(hkey, ValueName, 0, tp, strBuff, leng1)
'注意，第三个叁数传0，leng1传回copy 到strBuff的字元个数(anci)
leng1 = InStr(1, strBuff, Chr(0), vbBinaryCompare) '重新算个数(UniCode)
ResultStr = Left(StrBuff,leng1-1) '这便是ProductId的值
*****************************************************************************
在这里有另外一件事要特别说明，范例三程式中有一行leng1=Len(strBuffer)+1，
这行可省不得，很奇怪吧，为什麽明明是一个传回值，却一定要设定给它一个strBuff
的大小呢？这是因为许多WIN API 不会聪明到找strBuff的Null Char在哪里，所以需要
程式传进去，而後它再依这个栏位传回填入strBuff 的数目。
五、Array叁数的传递
我们知道Win API 的阵列传递是传阵列的起始位址，所以了，在VB中唯一要注意的
是起始位置的写法。以另一个取得Window目录所在路径的API为
例：
-----------------------------------------------------------------------------
UINT GetWindowsDirectory(
LPTSTR lpBuffer, // address of buffer for Windows director上一页 [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] 下一页
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