Shell Execute bring Window to front

Question

I'm using this function to call an executable from my MSI. However the window for the executable hides behind my MSI window. Is there any way to bring it to the front?

I have tried minimizing all the windows just before the call to ShellExecute but that still does not bring the executable window to the front.

extern "C" UINT __stdcall InstallDrivers(MSIHANDLE hInstall)
{
HRESULT hr = S_OK;
UINT er = ERROR_SUCCESS;
HANDLE hFile = INVALID_HANDLE_VALUE;
BYTE* pbData = NULL;
DWORD cbData = 0;
char pwzFilename[MAX_PATH], szDriverType[MAX_PATH], pwzSentinelFilename[MAX_PATH], szIsInstalled[MAX_PATH];
LPWSTR szValueBuf = NULL, szIsHaspInstalled = NULL, szIsSentinelInstalled = NULL;

hr = WcaInitialize(hInstall, "InstallDrivers");
ExitOnFailure(hr, "Failed to initialize");

WcaLog(LOGMSG_STANDARD, "Initialized.");
WcaLog(LOGMSG_STANDARD, "%s", szValueBuf);
CreateDirectory("C:\\Temp", NULL);

strcpy_s(pwzFilename, "C:\\Temp\\HASPUserSetup.exe");

hr = ExtractBinary(L"Hasp", &pbData, &cbData);
ExitOnFailure(hr, "failed to extract binary data");

if ((hFile = CreateFile(pwzFilename, GENERIC_WRITE,FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) 
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not create new temporary file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;  
} 

DWORD cbWritten = 0;
if ( !WriteFile(hFile, pbData, cbData, &cbWritten, NULL) )
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not write to file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;
}

CloseHandle(hFile);

strcpy_s(pwzSentinelFilename, "C:\\Temp\\sentinel_setup.exe");
hr = ExtractBinary(L"Sentinel", &pbData, &cbData);
ExitOnFailure(hr, "failed to extract binary data");

if ((hFile = CreateFile(pwzSentinelFilename, GENERIC_WRITE,FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) 
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not create new temporary file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;  
} 


if ( !WriteFile(hFile, pbData, cbData, &cbWritten, NULL) )
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not write to file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;
}

CloseHandle(hFile);

hr = WcaGetProperty(L"DRIVER", &szValueBuf);
ExitOnFailure(hr, "failed to get driver info");

wcstombs(szDriverType, szValueBuf, 260);
if (strcmp(szDriverType, "Hasp") == 0)
{   

    hr = WcaGetProperty(L"SENTINELINSTALLED", &szIsSentinelInstalled);
    ExitOnFailure(hr, "failed to get driver info");
    wcstombs(szIsInstalled, szValueBuf, 260);
    if (strcmp(szIsInstalled, "Sentinel Protection Installer 7.6.5") == 0)
    {
    ShellExecute(NULL, "open",  pwzSentinelFilename, NULL, NULL, SW_SHOWNORMAL);
    }
    ShellExecute(NULL, "open",  pwzFilename, NULL, NULL, SW_SHOWNORMAL);
}else
{
    hr = WcaGetProperty(L"HASPINSTALLED", &szIsHaspInstalled);
    ExitOnFailure(hr, "failed to get driver info");
    wcstombs(szIsInstalled, szIsHaspInstalled, 260);
    if (strcmp(szIsInstalled, "Sentinel Runtime") == 0)
    {
    ShellExecute(NULL, "open",  pwzFilename, NULL, NULL, SW_SHOWNORMAL);
    }
    ShellExecute(NULL, "open",  pwzSentinelFilename, NULL, NULL, SW_SHOWNORMAL);
}
LExit:
er = SUCCEEDED(hr) ? ERROR_SUCCESS : ERROR_INSTALL_FAILURE;
return WcaFinalize(er);
}

Updated Code:

extern "C" UINT __stdcall InstallDrivers(MSIHANDLE hInstall)
{
HRESULT hr = S_OK;
UINT er = ERROR_SUCCESS;
HANDLE hFile = INVALID_HANDLE_VALUE;
BYTE* pbData = NULL;
DWORD cbData = 0;
char pwzFilename[MAX_PATH], szDriverType[MAX_PATH], pwzSentinelFilename[MAX_PATH], szIsInstalled[MAX_PATH];
LPWSTR szValueBuf = NULL, szIsHaspInstalled = NULL, szIsSentinelInstalled = NULL;
SHELLEXECUTEINFO ShExecInfo;

ShExecInfo.cbSize = sizeof(SHELLEXECUTEINFO);
ShExecInfo.fMask = NULL;
ShExecInfo.hwnd = NULL;
ShExecInfo.lpVerb = NULL;
ShExecInfo.lpParameters = NULL;
ShExecInfo.lpDirectory = NULL;
ShExecInfo.nShow = SW_SHOWNORMAL;
ShExecInfo.hInstApp = NULL;

hr = WcaInitialize(hInstall, "InstallDrivers");
ExitOnFailure(hr, "Failed to initialize");

WcaLog(LOGMSG_STANDARD, "Initialized.");
WcaLog(LOGMSG_STANDARD, "%s", szValueBuf);
CreateDirectory("C:\\Temp", NULL);

strcpy_s(pwzFilename, "C:\\Temp\\HASPUserSetup.exe");

hr = ExtractBinary(L"Hasp", &pbData, &cbData);
ExitOnFailure(hr, "failed to extract binary data");

if ((hFile = CreateFile(pwzFilename, GENERIC_WRITE,FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) 
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not create new temporary file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;  
} 

DWORD cbWritten = 0;
if ( !WriteFile(hFile, pbData, cbData, &cbWritten, NULL) )
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not write to file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;
}

CloseHandle(hFile);

strcpy_s(pwzSentinelFilename, "C:\\Temp\\sentinel_setup.exe");
hr = ExtractBinary(L"Sentinel", &pbData, &cbData);
ExitOnFailure(hr, "failed to extract binary data");

if ((hFile = CreateFile(pwzSentinelFilename, GENERIC_WRITE,FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) 
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not create new temporary file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;  
} 


if ( !WriteFile(hFile, pbData, cbData, &cbWritten, NULL) )
{
    PMSIHANDLE hRecord = MsiCreateRecord(0);
    MsiRecordSetString(hRecord, 0, TEXT("Could not write to file"));
    MsiProcessMessage(hInstall, INSTALLMESSAGE(INSTALLMESSAGE_ERROR + MB_OK), hRecord);
    return ERROR_INSTALL_USEREXIT;
}

CloseHandle(hFile);

hr = WcaGetProperty(L"DRIVER", &szValueBuf);
ExitOnFailure(hr, "failed to get driver info");

wcstombs(szDriverType, szValueBuf, 260);
if (strcmp(szDriverType, "Hasp") == 0)
{   

    hr = WcaGetProperty(L"SENTINELINSTALLED", &szIsSentinelInstalled);
    ExitOnFailure(hr, "failed to get driver info");
    wcstombs(szIsInstalled, szValueBuf, 260);
    if (strcmp(szIsInstalled, "Sentinel Protection Installer 7.6.5") == 0)
    {
        AllowSetForegroundWindow(ASFW_ANY);
        ShExecInfo.lpFile = pwzSentinelFilename;
        ShellExecuteEx(&ShExecInfo);
        /*ShellExecute(NULL, "open",  pwzSentinelFilename, NULL, NULL, SW_SHOWNORMAL);*/
    }
    AllowSetForegroundWindow(ASFW_ANY);
    ShExecInfo.lpFile = pwzFilename;
    ShellExecuteEx(&ShExecInfo);

    /*ShellExecute(NULL, "open",  pwzFilename, NULL, NULL, SW_SHOWNORMAL);*/
}else
{
    hr = WcaGetProperty(L"HASPINSTALLED", &szIsHaspInstalled);
    ExitOnFailure(hr, "failed to get driver info");
    wcstombs(szIsInstalled, szIsHaspInstalled, 260);
    if (strcmp(szIsInstalled, "Sentinel Runtime") == 0)
    {
        AllowSetForegroundWindow(ASFW_ANY);
        /*ShellExecute(NULL, "open",  pwzFilename, NULL, NULL, SW_SHOWNORMAL);*/
        ShExecInfo.lpFile = pwzFilename;
        ShellExecuteEx(&ShExecInfo);
    }
    AllowSetForegroundWindow(ASFW_ANY);
    ShExecInfo.lpFile = pwzSentinelFilename;
    ShellExecuteEx(&ShExecInfo);
    /*  ShellExecute(NULL, "open",  pwzSentinelFilename, NULL, NULL, SW_SHOWNORMAL);*/
}
LExit:
er = SUCCEEDED(hr) ? ERROR_SUCCESS : ERROR_INSTALL_FAILURE;
return WcaFinalize(er);
}

Answer 1

Windows doesn't permit processes to snatch the foreground window unless the user starts them. This is to avoid things like persuading the user to type their bank details into the wrong window. However the current foreground process can pass permission to another process to do this. See AllowSetForegroundWindow for the details. To do this you have to provide the process id for the process that will become foreground and ShellExecute doesn't provide that. However, if you switch to using ShellExecuteEx you can get this from the hProcess member on the SHELLEXECUTEINFO structure.

You can then call SetForegroundWindow in your new process and it will be permitted. Otherwise it just starts flashing on the taskbar.

EDIT

If your initial application is the foreground application and you start a subprocess from that then the subprocess should automatically become foreground as described in the documentation for these functions.

Below is an example of how we can choose to enable and set another application to become the foreground window. In this case it just creates a text file and calls ShellExecuteEx with the open verb. We have to wait for the child process to get going and to have its window prepared and then we can locate the window from the process ID and give it permissions and set its window to be foreground. In this case the launched notepad (or whatever is your "open" verb for .txt files) will be foreground anyway. If you separately run a notepad process and substiture in the process ID for that process where we normally put in the child process ID then we can make another process become foreground -- one that is not part of our process tree. This can be compiled using Visual C++ with cl -nologo -W3 -O2 -MD fg_test.cpp to produce an fg_test.exe.

#define STRICT
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#include <shellapi.h>

#pragma comment(lib, "shell32")
#pragma comment(lib, "user32")

static void PrintError(LPCTSTR szPrefix, DWORD dwError);
static BOOL CALLBACK OnGetWindowByProcess(HWND hwnd, LPARAM lParam);

typedef struct {
    DWORD pid;
    HWND hwnd;
} WINDOWPROCESSINFO;

int _tmain(int argc, TCHAR *argv[])
{
    SHELLEXECUTEINFO sxi = {0};
    sxi.cbSize = sizeof(sxi);
    sxi.nShow = SW_SHOWNORMAL;

    FILE *fp = NULL;
    _tfopen_s(&fp, _T("junk.txt"), _T("wt"));
    _fputts(_T("Example text file\n"), fp);
    fclose(fp);

    sxi.fMask = SEE_MASK_NOCLOSEPROCESS | SEE_MASK_NOASYNC | SEE_MASK_WAITFORINPUTIDLE;
    sxi.lpVerb = _T("open");
    sxi.lpFile = _T("junk.txt");
    if (!ShellExecuteEx(&sxi))
        PrintError(_T("ShellExecuteEx"), GetLastError());
    else
    {
        WINDOWPROCESSINFO info;
        info.pid = GetProcessId(sxi.hProcess); // SPECIFY PID
        info.hwnd = 0;
        AllowSetForegroundWindow(info.pid);
        EnumWindows(OnGetWindowByProcess, (LPARAM)&info);
        if (info.hwnd != 0)
        {
            SetForegroundWindow(info.hwnd);
            SetActiveWindow(info.hwnd);
        }
        CloseHandle(sxi.hProcess);

    }
    return 0;
}

static BOOL CALLBACK OnGetWindowByProcess(HWND hwnd, LPARAM lParam)
{
    WINDOWPROCESSINFO *infoPtr = (WINDOWPROCESSINFO *)lParam;
    DWORD check = 0;
    BOOL br = TRUE;
    GetWindowThreadProcessId(hwnd, &check);
    _tprintf(_T("%x %x %x\n"), hwnd, check, infoPtr->pid);
    if (check == infoPtr->pid)
    {
        _tprintf(_T("found window %x for process id %x\n"), hwnd, check);
        infoPtr->hwnd = hwnd;
        br = FALSE;
    }
    return br;
}

static void
PrintError(LPCTSTR szPrefix, DWORD dwError)
{
    LPTSTR lpsz = NULL;
    DWORD cch = 0;

    cch = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER
                        | FORMAT_MESSAGE_FROM_SYSTEM
                        | FORMAT_MESSAGE_IGNORE_INSERTS,
                        NULL, dwError, LANG_NEUTRAL, (LPTSTR)&lpsz, 0, NULL);
    if (cch < 1) {
        cch = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER
                            | FORMAT_MESSAGE_FROM_STRING
                            | FORMAT_MESSAGE_ARGUMENT_ARRAY,
                            _T("Code 0x%1!08x!"),
                            0, LANG_NEUTRAL, (LPTSTR)&lpsz, 0,
                            (va_list*)&dwError);
    }
    _ftprintf(stderr, _T("%s: %s"), szPrefix, lpsz);
    LocalFree((HLOCAL)lpsz);
}