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;
}