Räkna upp registerundernycklar
I följande exempel används funktionerna RegQueryInfoKey, RegEnumKeyExoch RegEnumValue för att räkna upp undernycklarna för den angivna nyckeln. Parametern hKey som skickas till varje funktion är ett handtag till en öppen nyckel. Den här nyckeln måste öppnas innan funktionsanropet och stängs efteråt.
// QueryKey - Enumerates the subkeys of key and its associated values.
// hKey - Key whose subkeys and values are to be enumerated.
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#define MAX_KEY_LENGTH 255
#define MAX_VALUE_NAME 16383
void QueryKey(HKEY hKey)
{
TCHAR achKey[MAX_KEY_LENGTH]; // buffer for subkey name
DWORD cbName = 0; // size of name string
TCHAR achClass[MAX_PATH] = TEXT(""); // buffer for class name
DWORD cchClassName = MAX_PATH; // size of class string
DWORD cSubKeys = 0; // number of subkeys
DWORD cbMaxSubKey = 0; // longest subkey size
DWORD cchMaxClass = 0; // longest class string
DWORD cValues = 0; // number of values for key
DWORD cchMaxValue = 0; // longest value name
DWORD cbMaxValueData = 0; // longest value data
DWORD cbSecurityDescriptor = 0; // size of security descriptor
FILETIME ftLastWriteTime; // last write time
DWORD i = 0, j = 0, retCode = 0;
TCHAR achValue[MAX_VALUE_NAME] = {'\0'};
DWORD cchValue = MAX_VALUE_NAME;
// Get the class name and the value count.
retCode = ::RegQueryInfoKey(
hKey, // key handle
achClass, // buffer for class name
&cchClassName, // size of class string
NULL, // reserved
&cSubKeys, // number of subkeys
&cbMaxSubKey, // longest subkey size
&cchMaxClass, // longest class string
&cValues, // number of values for this key
&cchMaxValue, // longest value name
&cbMaxValueData, // longest value data
&cbSecurityDescriptor, // security descriptor
&ftLastWriteTime); // last write time
// Enumerate the subkeys, until RegEnumKeyEx fails.
if (cSubKeys)
{
printf("\nNumber of subkeys: %d\n", cSubKeys);
for (i = 0; i < cSubKeys; i++)
{
cbName = MAX_KEY_LENGTH;
retCode = ::RegEnumKeyEx(hKey, i,
achKey,
&cbName,
NULL,
NULL,
NULL,
&ftLastWriteTime);
if (retCode == ERROR_SUCCESS)
{
_tprintf(TEXT("(%d) %s\n"), i + 1, achKey);
}
}
}
// Enumerate the key values.
if (cValues)
{
printf("\nNumber of values: %d\n", cValues);
for (i = 0; i < cValues; i++)
{
cchValue = MAX_VALUE_NAME;
achValue[0] = '\0';
retCode = ::RegEnumValue(hKey, i,
achValue,
&cchValue,
NULL,
NULL,
NULL,
NULL);
if (retCode == ERROR_SUCCESS)
{
_tprintf(TEXT("(%d) %s\n"), i + 1, achValue);
}
}
}
}
int __cdecl _tmain()
{
HKEY hTestKey = 0;
if (::RegOpenKeyEx(HKEY_CURRENT_USER,
TEXT("SOFTWARE\\Microsoft"),
0,
KEY_READ,
&hTestKey) == ERROR_SUCCESS
)
{
QueryKey(hTestKey);
}
::RegCloseKey(hTestKey);
return 0;
}