Specify the registry uninstall key location/hive via [Code]

Question

Inno Setup by default looks at the PrivilegesRequired setup variable, if this is set to admin or poweruser, the installer installs the

Answer 1

The PrivilegesRequired=none solution was not what I wanted. In some cases, it still prompts for elevation on administrator accounts and also the registry destination was still not reflective of the users selection.

Since I was already using a native helper DLL in my Inno Setup project, I coded this in C++ as I'm more comfortable there. I'm calling this method is called in CurStepChanged where CurPage=ssDoneInstall. Just call this method with the [Setup] AppId and whether or not the registry keys should be installed locally or not.

#include 
extern "C" __declspec(dllexport)
bool DetectAndMoveRegKeyW(LPCWSTR app_id, bool install_local)
{
    std::wstring s_app = app_id;
    std::wstring path =
        L"Software\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\" + s_app + L"_is1";
    LPCWSTR c_path = path.c_str();

    LRESULT res;
    HKEY source = nullptr, subKey = nullptr;

    // try to find source in HKLM
    source = HKEY_LOCAL_MACHINE;
    res = RegOpenKeyExW(source, c_path, 0, KEY_READ, &subKey);
    if (subKey != nullptr)
        RegCloseKey(subKey);

    // try to find source in HKCU
    if (res != ERROR_SUCCESS)
    {
        subKey = nullptr;
        source = HKEY_CURRENT_USER;
        res = RegOpenKeyExW(source, c_path, 0, KEY_READ, &subKey);
        if (subKey != nullptr)
            RegCloseKey(subKey);
    }

    if (res != ERROR_SUCCESS)
        return false; // cant find the registry key

    HKEY dest = install_local ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE;
    if (source == dest)
        return true; // registry already in the right place


    // copy registry key to correct destination
    HKEY hOldKey;
    HKEY hNewKey;
    bool bResult = false;
    if (RegOpenKeyW(source, c_path, &hOldKey) == 0)
    {
        if (RegCreateKeyW(dest, c_path, &hNewKey) == 0)
        {
            bResult = (SHCopyKeyW(hOldKey, nullptr, hNewKey, 0) == 0);
            RegCloseKey(hNewKey);
        }
        RegCloseKey(hOldKey);

        if (bResult)
        {
            RegDeleteKeyW(source, c_path);
        }
    }

    return bResult;
}

I'm exporting this method as cdecl instead of stdcall, this is because VC++ ignores the C extern and mangles method names anyways when using stdcall. You'll need to import this as cdecl in inno (see inno docs for this). Also, of course this is the Unicode-only implementation, if you require an Ansi version it should be simple enough.

IMPORTANT NOTICE:
This code is incomplete, it doesn't account for 64bit registry redirection. Inno-Setup completely ignores windows registry redirection and this code doesn't search the 64 bit registry at all since Inno and itself are running in 32bit.