C++20&Win API&WIL コンポーネントカテゴリマネージャーを使う

CLSID_StdComponentCategoriesMgrとICatInformationインターフェイスを使ってコンポーネントカテゴリの情報を取得するコードです。カテゴリの概要や所属するクラスを列挙できます。

カテゴリの概要を列挙する

#include <string>

#define STRICT
#define NOMINMAX
#include <Windows.h>
#include <ShlObj.h>

// WIL
#include <wil/com.h>

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
    auto coinit{ wil::CoInitializeEx(COINIT_APARTMENTTHREADED) };

    auto catInfo{wil::CoCreateInstance<ICatInformation>(CLSID_StdComponentCategoriesMgr)};
    wil::com_ptr<IEnumCATEGORYINFO> enumCatInfo;
    catInfo->EnumCategories(0, enumCatInfo.put());

    CATEGORYINFO info;
    ULONG fetched;
    std::wstring output;
    while (enumCatInfo->Next(1, &info, &fetched) == S_OK)
    {
        output += info.szDescription;
        output += L"\r\n";
    }

    ::MessageBoxW(nullptr, output.c_str(), L"", MB_OK);

    return 0;
}

DeskBandカテゴリのクラスのCLSID・概要を列挙する

#include <bit>
#include <format>
#include <string>

#define STRICT
#define NOMINMAX
#include <Windows.h>
#include <ShlObj.h>

// WIL
#include <wil/com.h>
#include <wil/resource.h>

std::wstring CLSIDToWString(const CLSID& clsid)
{
    std::wstring s(38, '\0');
    if (FAILED(::StringFromGUID2(clsid, s.data(), 39)))
        return {};
    return std::move(s);
}

std::wstring RegQueryStringValue(
    HKEY hkey,
    std::wstring_view valueName)
{
    DWORD type;
    DWORD size;
    if (::RegQueryValueEx(hkey, valueName.data(), nullptr, &type,
        nullptr, &size) != ERROR_SUCCESS)
    {
        return {};
    }
    if (type != REG_SZ && type != REG_EXPAND_SZ)
    {
        return {};
    }

    std::wstring buffer(size / sizeof(wchar_t) - 1, L'\0');
    if (::RegQueryValueEx(hkey, valueName.data(), nullptr, &type,
        std::bit_cast<LPBYTE>(buffer.data()), &size) != NOERROR)
    {
        return {};
    }
    return std::move(buffer);
}

std::wstring RegQueryStringValue(
    HKEY hkey,
    std::wstring_view subKey,
    DWORD samDesired,
    std::wstring_view valueName)
{
    wil::unique_hkey hkeySub;
    if (::RegOpenKeyExW(hkey, subKey.data(), 0, samDesired, hkeySub.put()) != ERROR_SUCCESS)
        return {};
    return RegQueryStringValue(hkeySub.get(), valueName);
}

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
    auto coinit{ wil::CoInitializeEx(COINIT_APARTMENTTHREADED) };

    auto catInfo{ wil::CoCreateInstance<ICatInformation>(CLSID_StdComponentCategoriesMgr) };
    wil::com_ptr<IEnumCLSID> enumClsid;
    THROW_IF_FAILED(catInfo->EnumClassesOfCategories(1, &CATID_DeskBand, 0, nullptr, &enumClsid));

    CLSID clsid;
    ULONG fetched;
    std::wstring output;
    while (enumClsid->Next(1, &clsid, &fetched) == S_OK)
    {
        wil::unique_hkey clsidKey;
        auto clsidStr{ CLSIDToWString(clsid) };
        auto subKeyName{ std::format(L"CLSID\\{}", clsidStr) };
        output += std::format(L"{} {}\r\n",
            clsidStr,
            RegQueryStringValue(HKEY_CLASSES_ROOT, subKeyName, KEY_READ | KEY_WOW64_64KEY, L""));
    }

    ::MessageBoxW(nullptr, output.c_str(), L"", MB_OK);

    return 0;
}