鉴于某些注册表值的关键（例如HKEY_LOCAL_MACHINE \ blah \ blah \ blah \ foo），我该如何：
我绝对没有打算将任何内容写回注册表（如果我可以提供帮助，我将在我的职业生涯中）。因此，如果我错误地写入注册表，我们可以跳过关于我体内每个分子以光速爆炸的讲座。
首选C ++中的答案，但大多只需要知道特殊的Windows API咒语是什么。
答案 0 :(得分：62)
以下是一些用于检索以下内容的伪代码：
示例代码：
包含库依赖项：Advapi32.lib
HKEY hKey;
LONG lRes = RegOpenKeyExW(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Perl", 0, KEY_READ, &hKey);
bool bExistsAndSuccess (lRes == ERROR_SUCCESS);
bool bDoesNotExistsSpecifically (lRes == ERROR_FILE_NOT_FOUND);
std::wstring strValueOfBinDir;
std::wstring strKeyDefaultValue;
GetStringRegKey(hKey, L"BinDir", strValueOfBinDir, L"bad");
GetStringRegKey(hKey, L"", strKeyDefaultValue, L"bad");
LONG GetDWORDRegKey(HKEY hKey, const std::wstring &strValueName, DWORD &nValue, DWORD nDefaultValue)
{
nValue = nDefaultValue;
DWORD dwBufferSize(sizeof(DWORD));
DWORD nResult(0);
LONG nError = ::RegQueryValueExW(hKey,
strValueName.c_str(),
0,
NULL,
reinterpret_cast<LPBYTE>(&nResult),
&dwBufferSize);
if (ERROR_SUCCESS == nError)
{
nValue = nResult;
}
return nError;
}
LONG GetBoolRegKey(HKEY hKey, const std::wstring &strValueName, bool &bValue, bool bDefaultValue)
{
DWORD nDefValue((bDefaultValue) ? 1 : 0);
DWORD nResult(nDefValue);
LONG nError = GetDWORDRegKey(hKey, strValueName.c_str(), nResult, nDefValue);
if (ERROR_SUCCESS == nError)
{
bValue = (nResult != 0) ? true : false;
}
return nError;
}
LONG GetStringRegKey(HKEY hKey, const std::wstring &strValueName, std::wstring &strValue, const std::wstring &strDefaultValue)
{
strValue = strDefaultValue;
WCHAR szBuffer[512];
DWORD dwBufferSize = sizeof(szBuffer);
ULONG nError;
nError = RegQueryValueExW(hKey, strValueName.c_str(), 0, NULL, (LPBYTE)szBuffer, &dwBufferSize);
if (ERROR_SUCCESS == nError)
{
strValue = szBuffer;
}
return nError;
}
答案 1 :(得分：9)
const CString REG_SW_GROUP_I_WANT = _T("SOFTWARE\\My Corporation\\My Package\\Group I want");
const CString REG_KEY_I_WANT= _T("Key Name");
CRegKey regKey;
DWORD dwValue = 0;
if(ERROR_SUCCESS != regKey.Open(HKEY_LOCAL_MACHINE, REG_SW_GROUP_I_WANT))
{
m_pobLogger->LogError(_T("CRegKey::Open failed in Method"));
regKey.Close();
goto Function_Exit;
}
if( ERROR_SUCCESS != regKey.QueryValue( dwValue, REG_KEY_I_WANT))
{
m_pobLogger->LogError(_T("CRegKey::QueryValue Failed in Method"));
regKey.Close();
goto Function_Exit;
}
// dwValue has the stuff now - use for further processing
答案 2 :(得分：5)
RegOpenKey和RegQueryKeyEx对可以解决问题。
如果使用MFC CRegKey类则更容易解决。
答案 3 :(得分：4)
如果该值存在，则给出该值，如果该键不存在，则返回错误代码ERROR_FILE_NOT_FOUND。
（我不知道我的链接是否正常工作，但如果您只是谷歌“RegQueryValueEx”，那么第一个命中就是msdn文档。）
答案 4 :(得分：3)
由于Windows＆gt; = Vista / Server 2008，RegGetValue可用，is a safer function比RegQueryValueEx。无需RegOpenKeyEx，RegCloseKey或NUL字符串值终止检查（REG_SZ, REG_MULTI_SZ, REG_EXPAND_SZ）。
#include <iostream>
#include <string>
#include <exception>
#include <windows.h>
/*! \brief Returns a value from HKLM as string.
\exception std::runtime_error Replace with your error handling.
*/
std::wstring GetStringValueFromHKLM(const std::wstring& regSubKey, const std::wstring& regValue)
{
size_t bufferSize = 0xFFF; // If too small, will be resized down below.
std::wstring valueBuf; // Contiguous buffer since C++11.
valueBuf.resize(bufferSize);
auto cbData = static_cast<DWORD>(bufferSize);
auto rc = RegGetValueW(
HKEY_LOCAL_MACHINE,
regSubKey.c_str(),
regValue.c_str(),
RRF_RT_REG_SZ,
nullptr,
static_cast<void*>(&valueBuf.at(0)),
&cbData
);
while (rc == ERROR_MORE_DATA)
{
// Get a buffer that is big enough.
cbData /= sizeof(wchar_t);
if (cbData > static_cast<DWORD>(bufferSize))
{
bufferSize = static_cast<size_t>(cbData);
}
else
{
bufferSize *= 2;
cbData = static_cast<DWORD>(bufferSize);
}
valueBuf.resize(bufferSize);
rc = RegGetValueW(
HKEY_LOCAL_MACHINE,
regSubKey.c_str(),
regValue.c_str(),
RRF_RT_REG_SZ,
nullptr,
static_cast<void*>(&valueBuf.at(0)),
&cbData
);
}
if (rc == ERROR_SUCCESS)
{
valueBuf.resize(static_cast<size_t>(cbData / sizeof(wchar_t)));
return valueBuf;
}
else
{
throw std::runtime_error("Windows system error code: " + std::to_string(rc));
}
}
int main()
{
std::wstring regSubKey;
#ifdef _WIN64 // Manually switching between 32bit/64bit for the example. Use dwFlags instead.
regSubKey = L"SOFTWARE\\WOW6432Node\\Company Name\\Application Name\\";
#else
regSubKey = L"SOFTWARE\\Company Name\\Application Name\\";
#endif
std::wstring regValue(L"MyValue");
std::wstring valueFromRegistry;
try
{
valueFromRegistry = GetStringValueFromHKLM(regSubKey, regValue);
}
catch (std::exception& e)
{
std::cerr << e.what();
}
std::wcout << valueFromRegistry;
}
其参数dwFlags支持类型限制的标志，在失败时填充值缓冲区为零（RRF_ZEROONFAILURE）和32/64位注册表访问（RRF_SUBKEY_WOW6464KEY，RRF_SUBKEY_WOW6432KEY）对于64位程序。
答案 5 :(得分：0)
#include <windows.h>
#include <map>
#include <string>
#include <stdio.h>
#include <string.h>
#include <tr1/stdint.h>
using namespace std;
void printerr(DWORD dwerror) {
LPVOID lpMsgBuf;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
dwerror,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR) &lpMsgBuf,
0,
NULL
);
// Process any inserts in lpMsgBuf.
// ...
// Display the string.
if (isOut) {
fprintf(fout, "%s\n", lpMsgBuf);
} else {
printf("%s\n", lpMsgBuf);
}
// Free the buffer.
LocalFree(lpMsgBuf);
}
bool regreadSZ(string& hkey, string& subkey, string& value, string& returnvalue, string& regValueType) {
char s[128000];
map<string,HKEY> keys;
keys["HKEY_CLASSES_ROOT"]=HKEY_CLASSES_ROOT;
keys["HKEY_CURRENT_CONFIG"]=HKEY_CURRENT_CONFIG; //DID NOT SURVIVE?
keys["HKEY_CURRENT_USER"]=HKEY_CURRENT_USER;
keys["HKEY_LOCAL_MACHINE"]=HKEY_LOCAL_MACHINE;
keys["HKEY_USERS"]=HKEY_USERS;
HKEY mykey;
map<string,DWORD> valuetypes;
valuetypes["REG_SZ"]=REG_SZ;
valuetypes["REG_EXPAND_SZ"]=REG_EXPAND_SZ;
valuetypes["REG_MULTI_SZ"]=REG_MULTI_SZ; //probably can't use this.
LONG retval=RegOpenKeyEx(
keys[hkey], // handle to open key
subkey.c_str(), // subkey name
0, // reserved
KEY_READ, // security access mask
&mykey // handle to open key
);
if (ERROR_SUCCESS != retval) {printerr(retval); return false;}
DWORD slen=128000;
DWORD valuetype = valuetypes[regValueType];
retval=RegQueryValueEx(
mykey, // handle to key
value.c_str(), // value name
NULL, // reserved
(LPDWORD) &valuetype, // type buffer
(LPBYTE)s, // data buffer
(LPDWORD) &slen // size of data buffer
);
switch(retval) {
case ERROR_SUCCESS:
//if (isOut) {
// fprintf(fout,"RegQueryValueEx():ERROR_SUCCESS:succeeded.\n");
//} else {
// printf("RegQueryValueEx():ERROR_SUCCESS:succeeded.\n");
//}
break;
case ERROR_MORE_DATA:
//what do I do now? data buffer is too small.
if (isOut) {
fprintf(fout,"RegQueryValueEx():ERROR_MORE_DATA: need bigger buffer.\n");
} else {
printf("RegQueryValueEx():ERROR_MORE_DATA: need bigger buffer.\n");
}
return false;
case ERROR_FILE_NOT_FOUND:
if (isOut) {
fprintf(fout,"RegQueryValueEx():ERROR_FILE_NOT_FOUND: registry value does not exist.\n");
} else {
printf("RegQueryValueEx():ERROR_FILE_NOT_FOUND: registry value does not exist.\n");
}
return false;
default:
if (isOut) {
fprintf(fout,"RegQueryValueEx():unknown error type 0x%lx.\n", retval);
} else {
printf("RegQueryValueEx():unknown error type 0x%lx.\n", retval);
}
return false;
}
retval=RegCloseKey(mykey);
if (ERROR_SUCCESS != retval) {printerr(retval); return false;}
returnvalue = s;
return true;
}
答案 6 :(得分：0)
此控制台应用程序将从大多数可能的注册表值的注册表项中列出所有值及其数据。有些奇怪的东西不经常使用。如果您需要支持所有这些功能，请参考此Registry Value Type文档，从本示例中展开。
让它成为您可以从.reg文件格式导入的注册表项内容：
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\added\subkey]
"String_Value"="hello, world!"
"Binary_Value"=hex:01,01,01,01
"Dword value"=dword:00001224
"QWord val"=hex(b):24,22,12,00,00,00,00,00
"multi-line val"=hex(7):4c,00,69,00,6e,00,65,00,20,00,30,00,00,00,4c,00,69,00,\
6e,00,65,00,20,00,31,00,00,00,4c,00,69,00,6e,00,65,00,20,00,32,00,00,00,00,\
00
"expanded_val"=hex(2):25,00,55,00,53,00,45,00,52,00,50,00,52,00,4f,00,46,00,49,\
00,4c,00,45,00,25,00,5c,00,6e,00,65,00,77,00,5f,00,73,00,74,00,75,00,66,00,\
66,00,00,00
控制台应用程序本身：
#include <Windows.h>
#include <iostream>
#include <string>
#include <locale>
#include <vector>
#include <iomanip>
int wmain()
{
const auto hKey = HKEY_CURRENT_USER;
constexpr auto lpSubKey = TEXT("added\\subkey");
auto openedKey = HKEY();
auto status = RegOpenKeyEx(hKey, lpSubKey, 0, KEY_READ, &openedKey);
if (status == ERROR_SUCCESS) {
auto valueCount = static_cast<DWORD>(0);
auto maxNameLength = static_cast<DWORD>(0);
auto maxValueLength = static_cast<DWORD>(0);
status = RegQueryInfoKey(openedKey, NULL, NULL, NULL, NULL, NULL, NULL,
&valueCount, &maxNameLength, &maxValueLength, NULL, NULL);
if (status == ERROR_SUCCESS) {
DWORD type = 0;
DWORD index = 0;
std::vector<wchar_t> valueName = std::vector<wchar_t>(maxNameLength + 1);
std::vector<BYTE> dataBuffer = std::vector<BYTE>(maxValueLength);
for (DWORD index = 0; index < valueCount; index++) {
DWORD charCountValueName = static_cast<DWORD>(valueName.size());
DWORD charBytesData = static_cast<DWORD>(dataBuffer.size());
status = RegEnumValue(openedKey, index, valueName.data(), &charCountValueName,
NULL, &type, dataBuffer.data(), &charBytesData);
if (type == REG_SZ) {
const auto reg_string = reinterpret_cast<wchar_t*>(dataBuffer.data());
std::wcout << L"Type: REG_SZ" << std::endl;
std::wcout << L"\tName: " << valueName.data() << std::endl;
std::wcout << L"\tData : " << reg_string << std::endl;
}
else if (type == REG_EXPAND_SZ) {
const auto casted = reinterpret_cast<wchar_t*>(dataBuffer.data());
TCHAR buffer[32000];
ExpandEnvironmentStrings(casted, buffer, 32000);
std::wcout << L"Type: REG_EXPAND_SZ" << std::endl;
std::wcout << L"\tName: " << valueName.data() << std::endl;
std::wcout << L"\tData: " << buffer << std::endl;
}
else if (type == REG_MULTI_SZ) {
std::vector<std::wstring> lines;
const auto str = reinterpret_cast<wchar_t*>(dataBuffer.data());
auto line = str;
lines.emplace_back(line);
for (auto i = 0; i < charBytesData / sizeof(wchar_t) - 1; i++) {
const auto c = str[i];
if (c == 0) {
line = str + i + 1;
const auto new_line = reinterpret_cast<wchar_t*>(line);
if (wcsnlen_s(new_line, 1024) > 0)
lines.emplace_back(new_line);
}
}
std::wcout << L"Type: REG_MULTI_SZ" << std::endl;
std::wcout << L"\tName: " << valueName.data() << std::endl;
std::wcout << L"\tData: " << std::endl;
for (size_t i = 0; i < lines.size(); i++) {
std::wcout << L"\t\tLine[" << i + 1 << L"]: " << lines[i] << std::endl;
}
}
if (type == REG_DWORD) {
const auto dword_value = reinterpret_cast<unsigned long*>(dataBuffer.data());
std::wcout << L"Type: REG_DWORD" << std::endl;
std::wcout << L"\tName: " << valueName.data() << std::endl;
std::wcout << L"\tData : " << std::to_wstring(*dword_value) << std::endl;
}
else if (type == REG_QWORD) {
const auto qword_value = reinterpret_cast<unsigned long long*>(dataBuffer.data());
std::wcout << L"Type: REG_DWORD" << std::endl;
std::wcout << L"\tName: " << valueName.data() << std::endl;
std::wcout << L"\tData : " << std::to_wstring(*qword_value) << std::endl;
}
else if (type == REG_BINARY) {
std::vector<uint16_t> bins;
for (auto i = 0; i < charBytesData; i++) {
bins.push_back(static_cast<uint16_t>(dataBuffer[i]));
}
std::wcout << L"Type: REG_BINARY" << std::endl;
std::wcout << L"\tName: " << valueName.data() << std::endl;
std::wcout << L"\tData:";
for (size_t i = 0; i < bins.size(); i++) {
std::wcout << L" " << std::uppercase << std::hex << \
std::setw(2) << std::setfill(L'0') << std::to_wstring(bins[i]);
}
std::wcout << std::endl;
}
}
}
}
RegCloseKey(openedKey);
return 0;
}
预期的控制台输出：
Type: REG_SZ
Name: String_Value
Data : hello, world!
Type: REG_BINARY
Name: Binary_Value
Data: 01 01 01 01
Type: REG_DWORD
Name: Dword value
Data : 4644
Type: REG_DWORD
Name: QWord val
Data : 1188388
Type: REG_MULTI_SZ
Name: multi-line val
Data:
Line[1]: Line 0
Line[2]: Line 1
Line[3]: Line 2
Type: REG_EXPAND_SZ
Name: expanded_val
Data: C:\Users\user name\new_stuff
答案 7 :(得分：0)
通常，寄存器键和值在程序中是常量。如果是这样，这是一个示例，该示例如何读取DWORD注册表值Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled：
#include <windows.h>
DWORD val;
DWORD dataSize = sizeof(val);
if (ERROR_SUCCESS == RegGetValueA(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Control\\FileSystem", "LongPathsEnabled", RRF_RT_DWORD, nullptr /*type not required*/, &val, &dataSize)) {
printf("Value is %i\n", val);
// no CloseKey needed because it is a predefined registry key
}
else {
printf("Error reading.\n");
}
要适应其他值类型，请参阅https://docs.microsoft.com/en-us/windows/win32/api/winreg/nf-winreg-reggetvaluea以获取完整规范。