I'm trying to change the keyword property (under the Summary Information property set) of a folder.
I am aware that I can accomplish this using the StgCreatePropSetStg() function, which takes an IStorage object that will contain the property sets. I can then get an IStorage using StgCreateStorageEx().
One thing that bothers me is that I don't know how to make the generated IStorage object point to the path of the folder that I want to change the property.
I've tried to modify the sample in the documentation and ended up with this:
#include <stdio.h>
#include <windows.h>
#include <ole2.h>
int main() {
HRESULT hr = S_OK;
IPropertySetStorage *pPropSetStg = NULL;
IPropertyStorage *pPropStg = NULL;
WCHAR *pwszError = L"";
PROPSPEC propspec;
PROPVARIANT propvarWrite;
PROPVARIANT propvarRead;
try
{
// Create a file and a property set within it.
// ~~~~~ I`m not sure how to make an IStorage object point to a folder path
hr = StgCreateStorageEx( L"WriteRead.stg",
STGM_CREATE|STGM_SHARE_EXCLUSIVE|STGM_READWRITE,
STGFMT_STORAGE,
// STGFMT_STORAGE => Structured Storage
// property sets
// STGFMT_FILE => NTFS file system
// property sets
0, NULL, NULL,
IID_IPropertySetStorage,
reinterpret_cast<void**>(&pPropSetStg) );
if( FAILED(hr) ) throw L"Failed StgCreateStorageEx";
hr = pPropSetStg->Create( fmtid, NULL, PROPSETFLAG_DEFAULT,
STGM_CREATE|STGM_READWRITE|STGM_SHARE_EXCLUSIVE,
&pPropStg );
if( FAILED(hr) ) throw L"Failed IPropertySetStorage::Create";
// Write a Unicode string property to the property set
propspec.ulKind = PRSPEC_LPWSTR;
propspec.lpwstr = L"PIDSI_KEYWORDS";
propvarWrite.vt = VT_LPWSTR;
propvarWrite.pwszVal = L"Testing Tag";
hr = pPropStg->WriteMultiple( 1, &propspec, &propvarWrite,
PID_FIRST_USABLE );
if( FAILED(hr) )
throw L"Failed IPropertyStorage::WriteMultiple";
// Commit changes to the property set.
hr = pPropStg->Commit(STGC_DEFAULT);
if( FAILED(hr) )
throw L"Failed IPropertyStorage::Commit";
// Close and reopen everything.
pPropStg->Release(); pPropStg = NULL;
pPropSetStg->Release(); pPropSetStg = NULL;
}
catch( const WCHAR *pwszError )
{
wprintf( L"Error: %s (hr=%08x)\n", pwszError, hr );
}
PropVariantClear( &propvarRead );
if( pPropStg ) pPropStg->Release();
if( pPropSetStg ) pPropSetStg->Release();
}
Having said all of that,
My questions is: How to make the generated IStorage object point to a folder path?
Also, if I have some misconception about how IStorage works, please correct me.
Related
I am looking for a reliable method to map a DirectShow capture device GUID to its corresponding waveID value.
I found the following project by Chris_P:
The solution works great, and it relies on an a rather obscure IKsPropertySet interface to retrieve the mapping.
Unfortunately, if I attempt the same technique from a C++/CLI library, the code fails with E_NOTIMPL (this behavior has been described on this question, - see the answer by Vladimir Hmelyoff)
So, I figured that I could write a simple console-based auxiliary app to retrieve the mappings and print them. My library could then launch this auxiliary app and parse the redirected output to obtain the mappings.
The console program runs fine, however, the GUIDs that are being passed to the enumeration callback are completely different to the ones passed by Chris_P's solution.
In fact they all share the same basic structure:
lpGuid = 0x02ad0808 {BDF35A00-B9AC-11D0-A619-00AA00A7C000}
The only variation occurs in the last digits of the GUID, where coincidentally, they match the mapped waveId value.
Another weird thing is that the capture device description is truncated to 31 characters, as if the enumeration was being performed using WaveIn APIs!
It would almost seem that some DirectSound facade is now wrapping the WaveIn API.
Any pointers on what could be happening?, Can I disable this behavior and enumerate the same GUIDS that the WIN32 app is enumerating?
Here is the code for the console application:
#include "stdafx.h"
#include <mmreg.h>
#include <initguid.h>
#include <Dsound.h>
#include <dsconf.h>
static BOOL CALLBACK DSEnumCallback(
LPGUID lpGuid,
LPCTSTR lpcstrDescription,
LPCTSTR lpcstrModule,
LPVOID lpContext
);
static BOOL GetInfoFromDSoundGUID(GUID i_sGUID, DWORD &dwWaveID);
static HRESULT DirectSoundPrivateCreate(OUT LPKSPROPERTYSET * ppKsPropertySet);
typedef WINUSERAPI HRESULT(WINAPI *LPFNDLLGETCLASSOBJECT) (const CLSID &, const IID &, void **);
BOOL GetInfoFromDSoundGUID(GUID i_sGUID, DWORD &dwWaveID) {
LPKSPROPERTYSET pKsPropertySet = NULL;
HRESULT hr;
BOOL retval = FALSE;
PDSPROPERTY_DIRECTSOUNDDEVICE_DESCRIPTION_DATA psDirectSoundDeviceDescription = NULL;
DSPROPERTY_DIRECTSOUNDDEVICE_DESCRIPTION_DATA sDirectSoundDeviceDescription;
memset(&sDirectSoundDeviceDescription, 0, sizeof(sDirectSoundDeviceDescription));
hr = DirectSoundPrivateCreate(&pKsPropertySet);
if( SUCCEEDED(hr) ) {
ULONG ulBytesReturned = 0;
sDirectSoundDeviceDescription.DeviceId = i_sGUID;
// On the first call the final size is unknown so pass the size of the struct in order to receive
// "Type" and "DataFlow" values, ulBytesReturned will be populated with bytes required for struct+strings.
hr = pKsPropertySet->Get(DSPROPSETID_DirectSoundDevice,
DSPROPERTY_DIRECTSOUNDDEVICE_DESCRIPTION,
NULL,
0,
&sDirectSoundDeviceDescription,
sizeof(sDirectSoundDeviceDescription),
&ulBytesReturned
);
if( ulBytesReturned ) {
// On the first call it notifies us of the required amount of memory in order to receive the strings.
// Allocate the required memory, the strings will be pointed to the memory space directly after the struct.
psDirectSoundDeviceDescription = (PDSPROPERTY_DIRECTSOUNDDEVICE_DESCRIPTION_DATA)new BYTE[ulBytesReturned];
*psDirectSoundDeviceDescription = sDirectSoundDeviceDescription;
hr = pKsPropertySet->Get(DSPROPSETID_DirectSoundDevice,
DSPROPERTY_DIRECTSOUNDDEVICE_DESCRIPTION,
NULL,
0,
psDirectSoundDeviceDescription,
ulBytesReturned,
&ulBytesReturned
);
dwWaveID = psDirectSoundDeviceDescription->WaveDeviceId;
delete[] psDirectSoundDeviceDescription;
retval = TRUE;
}
pKsPropertySet->Release();
}
return retval;
}
HRESULT DirectSoundPrivateCreate(OUT LPKSPROPERTYSET * ppKsPropertySet) {
HMODULE hLibDsound = NULL;
LPFNDLLGETCLASSOBJECT pfnDllGetClassObject = NULL;
LPCLASSFACTORY pClassFactory = NULL;
LPKSPROPERTYSET pKsPropertySet = NULL;
HRESULT hr = DS_OK;
// Load dsound.dll
hLibDsound = LoadLibrary(TEXT("dsound.dll"));
if( !hLibDsound ) {
hr = DSERR_GENERIC;
}
// Find DllGetClassObject
if( SUCCEEDED(hr) ) {
pfnDllGetClassObject =
(LPFNDLLGETCLASSOBJECT)GetProcAddress(hLibDsound, "DllGetClassObject");
if( !pfnDllGetClassObject ) {
hr = DSERR_GENERIC;
}
}
// Create a class factory object
if( SUCCEEDED(hr) ) {
hr = pfnDllGetClassObject(CLSID_DirectSoundPrivate, IID_IClassFactory, (LPVOID *)&pClassFactory);
}
// Create the DirectSoundPrivate object and query for an IKsPropertySet
// interface
if( SUCCEEDED(hr) ) {
hr = pClassFactory->CreateInstance(NULL, IID_IKsPropertySet, (LPVOID *)&pKsPropertySet);
}
// Release the class factory
if( pClassFactory ) {
pClassFactory->Release();
}
// Handle final success or failure
if( SUCCEEDED(hr) ) {
*ppKsPropertySet = pKsPropertySet;
} else if( pKsPropertySet ) {
pKsPropertySet->Release();
}
FreeLibrary(hLibDsound);
return hr;
}
BOOL CALLBACK DSEnumCallback(
LPGUID lpGuid,
LPCTSTR lpcstrDescription,
LPCTSTR lpcstrModule,
LPVOID lpContext
) {
LPWSTR psz = NULL;
StringFromCLSID(*lpGuid, &psz);
DWORD WaveID = 0xFFFFFFFF;
if( lpGuid ) {
GUID i_guid = *lpGuid;
GetInfoFromDSoundGUID(i_guid, WaveID);
}
if( WaveID != 0xFFFFFFFF )
wprintf(_T("%d %s\r\n"), WaveID, psz);
if( psz ) {
CoTaskMemFree(psz);
}
return TRUE;
}
int main()
{
DirectSoundCaptureEnumerate(DSEnumCallback, NULL);
Sleep(10000);
return 0;
}
It turns out I was not initializing COM.
I added the following snippet at the beginning of my main() procedure and the program retrieved the expected GUIDs:
HRESULT hr = NULL;
hr = CoInitialize(NULL);
if( FAILED(hr) ) {
printf("Failed to initialize COM");
return -1;
}
So I guess that if COM is not initialized, the DirectSound engine falls back to the WaveIn API (creating a DirectShow facade around it).
I use filter DS LAME for compressing audio. I loaded it from file "lame.ax" as follows:
// pPath - path to LAME "lame.ax"
HRESULT CMyFilter::CreateObjectFromPath(wchar_t *pPath, REFCLSID clsid, IUnknown **ppUnk)
{
// load the target DLL directly
if (!m_hLibFilter) m_hLibFilter = LoadLibrary(pPath);
if (!m_hLibFilter)
{
return HRESULT_FROM_WIN32(GetLastError());
}
// the entry point is an exported function
FN_DLLGETCLASSOBJECT fn = (FN_DLLGETCLASSOBJECT)GetProcAddress(m_hLibFilter, "DllGetClassObject");
if (fn == NULL)
{
return HRESULT_FROM_WIN32(GetLastError());
}
// create a class factory
IUnknownPtr pUnk;
HRESULT hr = fn(clsid, IID_IUnknown, (void**)(IUnknown**)&pUnk);
if (SUCCEEDED(hr))
{
IClassFactoryPtr pCF = pUnk;
if (pCF == NULL)
{
hr = E_NOINTERFACE;
}
else
{
// ask the class factory to create the object
hr = pCF->CreateInstance(NULL, IID_IUnknown, (void**)ppUnk);
}
}
return hr;
}
further
HRESULT hr = 0;
IUnknown *ppUnk = 0;
ULONG lRef = 0;
hr = CreateObjectFromPath(L"lame.ax", CLSID_LAMEDShowFilter, (IUnknown **)&ppUnk);
hr = ppUnk->QueryInterface(&m_pFilter);
lRef = ppUnk->Release();
It works perfectly. LAME encoding audio.
I want to show the filter settings - property page, but this code failed
bool ShowConfigWindow(HWND hParent)
{
ISpecifyPropertyPages *pProp;
HRESULT hr = m_pFilter->QueryInterface(IID_ISpecifyPropertyPages, (void **)&pProp);
if (SUCCEEDED(hr))
{
// Get the filter's name and IUnknown pointer.
FILTER_INFO FilterInfo;
hr = m_pFilter->QueryFilterInfo(&FilterInfo);
IUnknown *pFilterUnk;
m_pFilter->QueryInterface(IID_IUnknown, (void **)&pFilterUnk);
// Show the page.
CAUUID caGUID;
pProp->GetPages(&caGUID);
pProp->Release();
HRESULT hr = OleCreatePropertyFrame(
hParent, // Parent window
0, 0, // Reserved
FilterInfo.achName, // Caption for the dialog box
1, // Number of objects (just the filter)
&pFilterUnk, // Array of object pointers.
caGUID.cElems, // Number of property pages
caGUID.pElems, // Array of property page CLSIDs
0, // Locale identifier
0, NULL // Reserved
);
// Clean up.
pFilterUnk->Release();
FilterInfo.pGraph->Release();
CoTaskMemFree(caGUID.pElems);
}
return true;
}
I find https://groups.google.com/forum/#!topic/microsoft.public.win32.programmer.directx.video/jknSbMenWeM
I should call CoRegisterClassObject for each property page, but how to do it?
Or what the right way?
OleCreatePropertyFrame takes property page class identifiers (CLSIDs) so you need to find a way to make them "visible" for the API.
Use of CoRegisterClassObject is one of the ways to achieve the mentioned task (perhaps the easiest, another method would be reg-free COM). You need to retrieve IClassFactory pointers for property page CLSIDs the same way as you do it in the first snippet. Then instead of calling IClassFactory::CreateInstance you use the interface pointers as arguments for CoRegisterClassObject API. Make sure you do it on the same thread as the following OleCreatePropertyFrame call. CoRevokeClassObject will clean things up afterwards.
How to read the target of shortcut file on windows. Tried using boost::read_symlink which throws exception saying "the file or directory is not a reparse point" message.
int main(int argc, _TCHAR* argv[])
{
try {
boost::filesystem::path target = boost::filesystem::read_symlink("c:\\tmp\\blobstore_2.lnk");
cout<<target.string();
} catch(const boost::filesystem::filesystem_error& ex)
{
cout<<"in catch"<<ex.what(); // prints "the file or directory is not a reparse point"
}
std::ifstream smbConfStream("c:\\tmp\\sym_file_2.lnk");
string ss((std::istreambuf_iterator<char>(smbConfStream)),
std::istreambuf_iterator<char>());
cout <<endl<<" ss: "<<ss; // From the output of the "ss" it looks like the information of the target is present inside ss along with other binary data. How to cleanly get the target out.
int i;
cin>>i;
return 0;
}
A Windows .lnk file is not a symbolic link. It is a shortcut file. You use the IShellLink interface to manipulate it.
The documentation contains the following example demonstrating how to resolve a shortcut file.
// ResolveIt - Uses the Shell's IShellLink and IPersistFile interfaces
// to retrieve the path and description from an existing shortcut.
//
// Returns the result of calling the member functions of the interfaces.
//
// Parameters:
// hwnd - A handle to the parent window. The Shell uses this window to
// display a dialog box if it needs to prompt the user for more
// information while resolving the link.
// lpszLinkFile - Address of a buffer that contains the path of the link,
// including the file name.
// lpszPath - Address of a buffer that receives the path of the link
// target, including the file name.
// lpszDesc - Address of a buffer that receives the description of the
// Shell link, stored in the Comment field of the link
// properties.
#include "stdafx.h"
#include "windows.h"
#include "shobjidl.h"
#include "shlguid.h"
#include "strsafe.h"
HRESULT ResolveIt(HWND hwnd, LPCSTR lpszLinkFile, LPWSTR lpszPath, int iPathBufferSize)
{
HRESULT hres;
IShellLink* psl;
WCHAR szGotPath[MAX_PATH];
WCHAR szDescription[MAX_PATH];
WIN32_FIND_DATA wfd;
*lpszPath = 0; // Assume failure
// Get a pointer to the IShellLink interface. It is assumed that CoInitialize
// has already been called.
hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_IShellLink, (LPVOID*)&psl);
if (SUCCEEDED(hres))
{
IPersistFile* ppf;
// Get a pointer to the IPersistFile interface.
hres = psl->QueryInterface(IID_IPersistFile, (void**)&ppf);
if (SUCCEEDED(hres))
{
WCHAR wsz[MAX_PATH];
// Ensure that the string is Unicode.
MultiByteToWideChar(CP_ACP, 0, lpszLinkFile, -1, wsz, MAX_PATH);
// Add code here to check return value from MultiByteWideChar
// for success.
// Load the shortcut.
hres = ppf->Load(wsz, STGM_READ);
if (SUCCEEDED(hres))
{
// Resolve the link.
hres = psl->Resolve(hwnd, 0);
if (SUCCEEDED(hres))
{
// Get the path to the link target.
hres = psl->GetPath(szGotPath, MAX_PATH, (WIN32_FIND_DATA*)&wfd, SLGP_SHORTPATH);
if (SUCCEEDED(hres))
{
// Get the description of the target.
hres = psl->GetDescription(szDescription, MAX_PATH);
if (SUCCEEDED(hres))
{
hres = StringCbCopy(lpszPath, iPathBufferSize, szGotPath);
if (SUCCEEDED(hres))
{
// Handle success
}
else
{
// Handle the error
}
}
}
}
}
// Release the pointer to the IPersistFile interface.
ppf->Release();
}
// Release the pointer to the IShellLink interface.
psl->Release();
}
return hres;
}
Here's more compact version of David's code, with ATL (included with Visual Studio).
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#include <ShObjIdl_core.h>
#include <atlstr.h>
#define CHECK( hr ) { const HRESULT __hr = ( hr ); if( FAILED( __hr ) ) return __hr; }
HRESULT resolveShortcutTarget( HWND wnd, const CString& lnk, CString& target )
{
// Get a pointer to the IShellLink interface. It is assumed that CoInitialize has already been called.
CComPtr<IShellLink> psl;
CHECK( psl.CoCreateInstance( CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER ) );
// Get a pointer to the IPersistFile interface.
CComPtr<IPersistFile> ppf;
CHECK( psl->QueryInterface( IID_PPV_ARGS( &ppf ) ) );
// Load the shortcut.
CHECK( ppf->Load( lnk, STGM_READ ) );
// Resolve the link.
CHECK( psl->Resolve( wnd, 0 ) );
// Get the path to the link target.
const HRESULT hr = psl->GetPath( target.GetBufferSetLength( MAX_PATH ), MAX_PATH, nullptr, 0 );
target.ReleaseBuffer();
return hr;
}
How to read the target of shortcut file on windows. Tried using boost::read_symlink which throws exception saying "the file or directory is not a reparse point" message.
int main(int argc, _TCHAR* argv[])
{
try {
boost::filesystem::path target = boost::filesystem::read_symlink("c:\\tmp\\blobstore_2.lnk");
cout<<target.string();
} catch(const boost::filesystem::filesystem_error& ex)
{
cout<<"in catch"<<ex.what(); // prints "the file or directory is not a reparse point"
}
std::ifstream smbConfStream("c:\\tmp\\sym_file_2.lnk");
string ss((std::istreambuf_iterator<char>(smbConfStream)),
std::istreambuf_iterator<char>());
cout <<endl<<" ss: "<<ss; // From the output of the "ss" it looks like the information of the target is present inside ss along with other binary data. How to cleanly get the target out.
int i;
cin>>i;
return 0;
}
A Windows .lnk file is not a symbolic link. It is a shortcut file. You use the IShellLink interface to manipulate it.
The documentation contains the following example demonstrating how to resolve a shortcut file.
// ResolveIt - Uses the Shell's IShellLink and IPersistFile interfaces
// to retrieve the path and description from an existing shortcut.
//
// Returns the result of calling the member functions of the interfaces.
//
// Parameters:
// hwnd - A handle to the parent window. The Shell uses this window to
// display a dialog box if it needs to prompt the user for more
// information while resolving the link.
// lpszLinkFile - Address of a buffer that contains the path of the link,
// including the file name.
// lpszPath - Address of a buffer that receives the path of the link
// target, including the file name.
// lpszDesc - Address of a buffer that receives the description of the
// Shell link, stored in the Comment field of the link
// properties.
#include "stdafx.h"
#include "windows.h"
#include "shobjidl.h"
#include "shlguid.h"
#include "strsafe.h"
HRESULT ResolveIt(HWND hwnd, LPCSTR lpszLinkFile, LPWSTR lpszPath, int iPathBufferSize)
{
HRESULT hres;
IShellLink* psl;
WCHAR szGotPath[MAX_PATH];
WCHAR szDescription[MAX_PATH];
WIN32_FIND_DATA wfd;
*lpszPath = 0; // Assume failure
// Get a pointer to the IShellLink interface. It is assumed that CoInitialize
// has already been called.
hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_IShellLink, (LPVOID*)&psl);
if (SUCCEEDED(hres))
{
IPersistFile* ppf;
// Get a pointer to the IPersistFile interface.
hres = psl->QueryInterface(IID_IPersistFile, (void**)&ppf);
if (SUCCEEDED(hres))
{
WCHAR wsz[MAX_PATH];
// Ensure that the string is Unicode.
MultiByteToWideChar(CP_ACP, 0, lpszLinkFile, -1, wsz, MAX_PATH);
// Add code here to check return value from MultiByteWideChar
// for success.
// Load the shortcut.
hres = ppf->Load(wsz, STGM_READ);
if (SUCCEEDED(hres))
{
// Resolve the link.
hres = psl->Resolve(hwnd, 0);
if (SUCCEEDED(hres))
{
// Get the path to the link target.
hres = psl->GetPath(szGotPath, MAX_PATH, (WIN32_FIND_DATA*)&wfd, SLGP_SHORTPATH);
if (SUCCEEDED(hres))
{
// Get the description of the target.
hres = psl->GetDescription(szDescription, MAX_PATH);
if (SUCCEEDED(hres))
{
hres = StringCbCopy(lpszPath, iPathBufferSize, szGotPath);
if (SUCCEEDED(hres))
{
// Handle success
}
else
{
// Handle the error
}
}
}
}
}
// Release the pointer to the IPersistFile interface.
ppf->Release();
}
// Release the pointer to the IShellLink interface.
psl->Release();
}
return hres;
}
Here's more compact version of David's code, with ATL (included with Visual Studio).
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#include <ShObjIdl_core.h>
#include <atlstr.h>
#define CHECK( hr ) { const HRESULT __hr = ( hr ); if( FAILED( __hr ) ) return __hr; }
HRESULT resolveShortcutTarget( HWND wnd, const CString& lnk, CString& target )
{
// Get a pointer to the IShellLink interface. It is assumed that CoInitialize has already been called.
CComPtr<IShellLink> psl;
CHECK( psl.CoCreateInstance( CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER ) );
// Get a pointer to the IPersistFile interface.
CComPtr<IPersistFile> ppf;
CHECK( psl->QueryInterface( IID_PPV_ARGS( &ppf ) ) );
// Load the shortcut.
CHECK( ppf->Load( lnk, STGM_READ ) );
// Resolve the link.
CHECK( psl->Resolve( wnd, 0 ) );
// Get the path to the link target.
const HRESULT hr = psl->GetPath( target.GetBufferSetLength( MAX_PATH ), MAX_PATH, nullptr, 0 );
target.ReleaseBuffer();
return hr;
}
Does anyone know how to get hold of the Excel.Application IDispatch* pointer associated with an excel process into which an dll has been loaded?
A key thing here is that the process is excel.exe, and the pointer I need must belong to that process. Using the Running Object Table will not fly since Excel only registers its first instance with that.
I'm hoping there is some low-level COM trickery, but I'm not an expert in that field.
EDITED II Code is under the WTFPL license version 2.
EDITED: Add PID parameter to allow filtering when several Excel processes are currently running, as per comment suggestion from #EricBrown.
I managed to get a working IDispatch* to an Excel "Application" object without using the ROT. The trick is to use MSAA. My code works as a stand alone console application, but I think that if the code is executed in an Excel process, via DLL Injection, it MAY works fine. You may have to be in a dedicated thread. Let me know if you want me to push the expriment to the DLL injection level.
Tested OK on Window7 64b, with a UNICODE builds (32 bits and 64 bits).
Excel version 2010 64 bits (version "14")
I get the IDispatch via the "application" property from an "Worksheet" object. Consequence: there must be an opened worksheet. In order to find the good MSSA Window, I need the class name of the Top Level Excel Frame Window. In Excel 2010, it's "XLMAIN". The class name for worksheets is "EXCEL7" and that seems to be a "standard".
I was not able to directly get a working IDispatch* from the main Excel Window, but have not tried very hard. That may involve #import with a automation DLL from Excel, in order to QueryInterface the IDispatch that MSAA gives for the main Window (that IDispatch is NOT for an Application object)
#include <atlbase.h>
#pragma comment( lib, "Oleacc.lib" )
HRESULT GetExcelAppDispatch( CComPtr<IDispatch> & spIDispatchExcelApp, DWORD dwExcelPID ) {
struct ew {
struct ep {
_TCHAR* pszClassName;
DWORD dwPID;
HWND hWnd;
};
static BOOL CALLBACK ewp( HWND hWnd, LPARAM lParam ) {
TCHAR szClassName[ 64 ];
if ( GetClassName( hWnd, szClassName, 64 ) ) {
ep* pep = reinterpret_cast<ep*>( lParam );
if ( _tcscmp( szClassName, pep->pszClassName ) == 0 ) {
if ( pep->dwPID == 0 ) {
pep->hWnd = hWnd;
return FALSE;
} else {
DWORD dwPID;
if ( GetWindowThreadProcessId( hWnd, &dwPID ) ) {
if ( dwPID == pep->dwPID ) {
pep->hWnd = hWnd;
return FALSE;
}
}
}
}
}
return TRUE;
}
};
ew::ep ep;
ep.pszClassName = _TEXT( "XLMAIN" );
ep.dwPID = dwExcelPID;
ep.hWnd = NULL;
EnumWindows( ew::ewp, reinterpret_cast<LPARAM>( &ep ) );
HWND hWndExcel = ep.hWnd;
if ( ep.hWnd == NULL ) {
printf( "Can't Find Main Excel Window with EnumWindows\n" );
return -1;
}
ep.pszClassName = _TEXT( "EXCEL7" );
ep.dwPID = 0;
ep.hWnd = NULL;
EnumChildWindows( hWndExcel, ew::ewp, reinterpret_cast<LPARAM>( &ep ) );
HWND hWndWorkSheet = ep.hWnd;
if ( hWndWorkSheet == NULL ) {
printf( "Can't Find a WorkSheet with EnumChildWindows\n" );
return -1;
}
CComPtr<IDispatch> spIDispatchWorkSheet;
HRESULT hr = AccessibleObjectFromWindow( hWndWorkSheet, OBJID_NATIVEOM, IID_IDispatch,
reinterpret_cast<void**>( &spIDispatchWorkSheet ) );
if ( FAILED( hr ) || ( spIDispatchWorkSheet == 0 ) ) {
printf( "AccessibleObjectFromWindow Failed\n" );
return hr;
}
CComVariant vExcelApp;
hr = spIDispatchWorkSheet.GetPropertyByName( CComBSTR( "Application" ), &vExcelApp );
if ( SUCCEEDED( hr ) && ( vExcelApp.vt == VT_DISPATCH ) ) {
spIDispatchExcelApp = vExcelApp.pdispVal;
return S_OK;
}
return hr;
}
int _tmain(int argc, _TCHAR* argv[])
{
DWORD dwExcelPID = 0;
if ( argc > 1 ) dwExcelPID = _ttol( argv[ 1 ] );
HRESULT hr = CoInitialize( NULL );
bool bCoUnInitializeTodo = false;
if ( SUCCEEDED( hr ) ) {
bCoUnInitializeTodo = true;
CComPtr<IDispatch> spDispatchExcelApp;
hr = GetExcelAppDispatch( spDispatchExcelApp, dwExcelPID );
if ( SUCCEEDED( hr ) && spDispatchExcelApp ) {
CComVariant vExcelVer;
hr = spDispatchExcelApp.GetPropertyByName( CComBSTR( "Version" ), &vExcelVer );
if ( SUCCEEDED( hr ) && ( vExcelVer.vt == VT_BSTR ) ) {
wprintf( L"Excel Version is %s\n", vExcelVer.bstrVal );
}
}
}
if ( bCoUnInitializeTodo ) CoUninitialize();
return 0;
}
You should be able to find out how to do this by reviewing the code in ExcelDNA. This project contains code that hooks back into Excel from the extension library. The code is likely to be more elaborate that you need, but will implement the reference you require.
This is how I do it: (acknowledge #manuell). dispatch_wrapper is a class, here is the constructor to set m_disp_application:
dispatch_wrapper(void)
{
DWORD target_process_id = ::GetProcessId(::GetCurrentProcess());
if (getProcessName() == "excel.exe"){
HWND hwnd = ::FindWindowEx(0, 0, "XLMAIN", NULL);
while (hwnd){
DWORD process_id;
::GetWindowThreadProcessId(hwnd, &process_id);
if (process_id == target_process_id){
HWND hwnd_desk = ::FindWindowEx(hwnd, 0, "XLDESK", NULL);
HWND hwnd_7 = ::FindWindowEx(hwnd_desk, 0, "EXCEL7", NULL);
IDispatch* p = nullptr;
if (SUCCEEDED(::AccessibleObjectFromWindow(hwnd_7, OBJID_NATIVEOM, IID_IDispatch, (void**)&p))){
LPOLESTR name[1] = {L"Application"};
DISPID dispid;
if (SUCCEEDED(p->GetIDsOfNames(IID_NULL, name, 1U, LOCALE_SYSTEM_DEFAULT, &dispid))){
CComVariant v;
DISPPARAMS dp;
::memset(&dp, NULL, sizeof(DISPPARAMS));
EXCEPINFO ei;
::memset(&ei, NULL, sizeof(EXCEPINFO));
if (SUCCEEDED(p->Invoke(dispid, IID_NULL, LOCALE_SYSTEM_DEFAULT, DISPATCH_PROPERTYGET, &dp, &v, &ei, NULL))){
if (v.vt == VT_DISPATCH){
m_disp_application = v.pdispVal;
m_disp_application->AddRef();
return;
}
}
}
}
}
hwnd = ::FindWindowEx(0, hwnd, "XLMAIN", NULL);
}
}
m_disp_application = nullptr;
}
getProcessName() returns lower case.
Because Office applications register their documents in the ROT, you can attach to instances beside the first one (which is already in the ROT) by getting IDispatch for documents in the ROT, then you can use document.Application.hwnd (this is VBA, you need to translate to IDispatch::GetIDsOfNames and IDispatch::Invoke with DISPATCH_PROPERTYGET) to get the window handles of all Excel instances.
Now you have a mapping between IDispatch and Windows handles of all Excel instances, it is time to find your own Excel instance. You can call GetWindowThreadProcessId on the window handles to get the process ids, then compare to your own process id returned by GetCurrentProcessId to see which excel window belongs to your current process, and look up in the HWND to IDispatch mapping to find your current Excel application's IDispatch interface.