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DllSurrogate problems Avneesh Bhatnagar3-Dec-01 18:38 Avneesh Bhatnagar 3-Dec-01 18:38  Hi! I am trying to use a dll hosted through DllHost.exe on a remote machine. Whn I try to run CoCreateInstance, my client (which is trying to access this dll on the remote machine) hangs, with no response. I tried to find out the problem by running OleView on the remote machine and slecting CreateInstance on the component. However I get this error: "CoGetClassObject" failed. Any recommendations? I have already registered the dll in question and also the proxy/stub Thanks in advance! Re: DllSurrogate problems Joao Morais5-Jan-02 0:36 Joao Morais 5-Jan-02 0:36  It sounds like the COM Runtime could not find the class factory. Here are some reasons: 1) your COM server is not registered in your client machine to be used remotely (if you use the implicit settings in the registry). 2) your COM server is not well registered in the server machine. 3) your COM server file (DLL) does not export the DllGetClassObject() method (seldom, but I already met it). I have written an article about "COM Macro-Architecture" (http://www.codeproject.com/com/macrotopomain.asp) where I show out different configurations for the COM server and the client application. You should have a look at the cases 8 & 9. Joao QueryInterface( ..., void** ppv) 3-Dec-01 9:26 3-Dec-01 9:26  Hi, could anybody explain please the reason for QueryInterface's second parameter being a double pointer? Thanks PP Re: QueryInterface( ..., void** ppv) Bill Wilson3-Dec-01 10:45 Bill Wilson 3-Dec-01 10:45  I believe it is so QueryInterface can return a pointer. Hope this helps, Bill Re: QueryInterface( ..., void** ppv) Shadi Al-Kahwaji9-Dec-01 22:41 Shadi Al-Kahwaji 9-Dec-01 22:41  Hi, Let us start from the begining of the C/C++ language without COM. In the C/C++ language, whenever you have a class which contains at least ONE Virtual Function/Pure Function, a virtual table will be created at run time for this class which contains a list of the virtual functions in that class, and a Hidden pointer which called _vPtr is returned, this pointer points to the first entry in the virtual table. Let us back to the COM world, QueryInterface is a method in the IUnknown interface, and IUknown interface is accessing the functionality of the component through virtual table. The interface which returned from the QueryInterface is NOT poiting to the virtual table directly, it points to the hidden pointer _vPtr which points to the virtual table. For this reason we have pointer to pointer. Regards, ShadiK. Shadi Al-Kahwaji Automatisation question - need hint Harald Krause2-Dec-01 6:25 Harald Krause 2-Dec-01 6:25  I have a COM server using MFC (.exe) It has some methods to remote control it, eg. like that in VB MyApplication = CreateObject(MyApplicationname.Application) MyApplication.DoSomething or has some methods who returns "built in" datatypes eg: aInteger = MyApplication.returnaingeger aBstring = MyApplication.returnaBstring That was pretty easy to do, in fact all work was done by the class wizzard... Now my problem: I need to return a other COM object or class like that: aClass = MyApplication.returnaClass so I could do something like that: aClass.somevalue = 1 Could anybody give me a hint how to do that, eg. point me to an article? Re: Automatisation question - need hint David Stranz3-Dec-01 6:53 David Stranz 3-Dec-01 6:53  You create the other COM object with an IDispatch-derived interface, then return that IDispatch pointer as the [out, retval] parameter to the call. Example from one of my controls (an X-Y data plot - IAxis is the COM object I want to return): -> IDL: [ object, uuid( /* GUID */), dual, helpstring("IDataplot Interface"), pointer_default(unique), nonextensible ] interface IDataplot : IDispatch { /* ... */ [ propget, id(5), helpstring("property AxisX")] HRESULT AxisX( [out, retval] IAxis * * ppVal ); } -> C++ .h file: STDMETHOD(get_AxisX)(/*[out, retval]*/ IAxis * * ppVal ); -> C++ .cpp file: STDMETHODIMP CDataplot::get_AxisX( IAxis * * ppVal ) { AFX_MANAGE_STATE(AfxGetStaticModuleState()) if ( 0 == ppVal ) return E_POINTER; *ppVal = 0; HRESULT hRes = S_OK; CComObject< CAxis > * pObj = 0; try { hRes = CComObject< CAxis >::CreateInstance( &pObj ); if ( SUCCEEDED( hRes ) ) { hRes = pObj->QueryInterface( IID_IAxis, (void * *)ppVal ); assert( SUCCEEDED( hRes ) ); } } catch( ... ) { hRes = E_OUTOFMEMORY; *ppVal = 0; } return hRes; } I hope this is legible - the message editor on this site is less than adequate for replying. Whose bright idea was it to set the width of the editing window to 20 characters, with automatic wrapping? Regards, David passing connection points parameters by ref SPENNER1-Dec-01 8:38 SPENNER 1-Dec-01 8:38  Does anyone know the trick to getting a connection point method to pass parameters by reference? Below is an example of a simple event, which should return a short from the client, but the variant varResult always returns empty?!? Any ideas? IDL: [ uuid(48053E7C-D307-40D2-A380-3B9CB25282AB), version(1.0), helpstring("atl_event 1.0 Type Library") ] library ATL_EVENTLib { importlib("stdole32.tlb"); importlib("stdole2.tlb"); [ uuid(224E5ED5-D64E-4556-A785-5ACE0DD8F0B3), helpstring("_IEventTestEvents Interface") ] dispinterface _IEventTestEvents { properties: methods: [id(1), helpstring("method TestEvent")] HRESULT TestEvent([in, out] short* sVar ); }; [ uuid(840EF1AE-F80F-4F71-9802-03DFE6555B19), helpstring("EventTest Class") ] coclass EventTest { [default] interface IEventTest; [default, source] dispinterface _IEventTestEvents; }; }; C++: template <class t=""> class CProxy_IEventTestEvents : public IConnectionPointImpl<t, &diid__ieventtestevents,="" ccomdynamicunkarray=""> { //Warning this class may be recreated by the wizard. public: HRESULT Fire_TestEvent(SHORT * sVar) { CComVariant varResult; T* pT = static_cast<t*>(this); int nConnectionIndex; CComVariant* pvars = new CComVariant[1]; int nConnections = m_vec.GetSize(); for (nConnectionIndex = 0; nConnectionIndex < nConnections; nConnectionIndex++) { pT->Lock(); CComPtr<iunknown> sp = m_vec.GetAt(nConnectionIndex); pT->Unlock(); IDispatch* pDispatch = reinterpret_cast<idispatch*>(sp.p); if (pDispatch != NULL) { VariantClear(&varResult); pvars[0] = *sVar; DISPPARAMS disp = { pvars, NULL, 1, 0 }; pDispatch->Invoke(0x1, IID_NULL, LOCALE_USER_DEFAULT, DISPATCH_METHOD, &disp, &varResult, NULL, NULL); } } delete[] pvars; // *sVar = varResult.iVal; return varResult.scode; } }; __scott Re: passing connection points parameters by ref Anders Molin1-Dec-01 10:56 Anders Molin 1-Dec-01 10:56  SPENNER wrote: [id(1), helpstring("method TestEvent")] HRESULT TestEvent([in, out] short* sVar ); Woops, you can't have out parameters on a connection point event function... If you need a parameter back from the client, you need to implement a callback interface instead of using connection points. - Anders Money talks, but all mine ever says is "Goodbye!" Re: passing connection points parameters by ref SPENNER1-Dec-01 11:38 SPENNER 1-Dec-01 11:38  That's odd... Because, and I know this isn't the best example, but if I create a quick COM object with VB and define an outgoing interface with a byref parameter, it works great. The resulting IDL is below: [id(0x00000001)] void TestEvent( [in] short eventByVal, [in, out] short* eventAsRef, [in, out] VARIANT_BOOL* eventBoolRef); So, I'm thinking there must be a C++/ATL equivalent, but I can't figure it out...I know I could use a call back interface, but using a connection point would make it more straight forward from the client side... Any idea how to get this to work? __scott Re: passing connection points parameters by ref Anders Molin1-Dec-01 12:50 Anders Molin 1-Dec-01 12:50  SPENNER wrote: Any idea how to get this to work? Nope, not right now. I have the "Inside ATL" book, but I left it at work... I'll try to see if there's a solution in there... (on monday when I get to work...) - Anders Money talks, but all mine ever says is "Goodbye!" Re: passing connection points parameters by ref Michael P Butler2-Dec-01 1:54 Michael P Butler 2-Dec-01 1:54  Are you sure that VB has generated a connnection point and not a custom event handler? Michael Re: passing connection points parameters by ref SPENNER2-Dec-01 9:51 SPENNER 2-Dec-01 9:51  That's one of the problems with VB, it's hard to know exactly what's going on. I guess my question should be, how do I create an event function that returns parameters from the client (without using a callback interface)? Anyone have a clue on this one? __scott Re: passing connection points parameters by ref Anders Molin2-Dec-01 10:55 Anders Molin 2-Dec-01 10:55  Why not just use the callback interface. It's easy to make in VC, and easy to use from VB... - Anders Money talks, but all mine ever says is "Goodbye!" Re: passing connection points parameters by ref SPENNER4-Dec-01 7:56 SPENNER 4-Dec-01 7:56  One of the good things about using connection points is that the client doesn't need to manage the connection to the incoming interface. That is, to connect to the COM server callback interface, the client must pass a reference of itself to the server. Is there a way for the server to determine if the client is still there before calling the callback function? Is there a way for the server to implicitly connect to the client when the client instantiates an object from the server? I'm not sure that made sense...oh well __scott Re: passing connection points parameters by ref Anders Molin4-Dec-01 8:11 Anders Molin 4-Dec-01 8:11  SPENNER wrote: I'm not sure that made sense...oh well I know exactly what you mean. I just don't know of a solution... - Anders Money talks, but all mine ever says is "Goodbye!" Using ActiveX Object inside ATL COM Object... Please Help Matt Philmon30-Nov-01 18:37 Matt Philmon 30-Nov-01 18:37  We have a communications ATL COM DLL used in a project here that used to load a Java COM object (on a web server) that communicates to a server running IMS transactions on a mainframe. The Java "object" was provided by the customer. Recently they "upgraded" to a newer component, an ActiveX DLL written in Microsoft J++. The old component wasn't a DLL, but a huge collection of Java class files. Because we couldn't import any DLL and had no Type Library to work with we had to do it the painful way, loading by ProgID (easy in VB, hard in ATL), getting the IDispatch pointer, and using Invoke. This new version comes as a DLL which means I can easily #import the DLL itself and use that to make me a good ol smart pointer which I can use. That part was easy and appears to be fine. My smart pointer is using a single method in the new object called "processITOC". Visual Assist shows me that format of this sucker is: _bstr_t processITOC ( BSTR * templatepath, BSTR * server, BSTR * port, BSTR * system, BSTR * UserId, BSTR * password, long * timeout, VARIANT * request, BSTR * sTranName ); Seems easy enough... more or less, I hate variants. However, every time I try to pass in the data, it blows with an Access Violation in MSVBVM60.DLL, 0xC0000005. I know this new DLL works fine because I can load it up in a VB project and use it just fine. However, in ATL it blows. I think I'm probably doing something really simple wrong but am currently lost. Could someone give me a hand? _bstr_t Ret; BSTR Template = L"file:///C:\\HostTemplates/"; BSTR LogDir = L"C:\\LOG\\"; BSTR Priority = L"3"; BSTR Mainframe = L"111.111.111.111"; WCHAR wchPort[10]; _itow(32000, wchPort, 10); BSTR Port = wchPort; BSTR User = L"user"; BSTR Password = L"password"; long Timeout = 240000; BSTR System = L"DatabaseName"; BSTR TransID = L"ID"; VARIANT upArg; VariantInit(&upArg); V_VT(&upArg) = VT_BSTR; V_BSTR(&upArg) = SysAllocString("ImAnXMLRequestwithtags"); m_pIHandler->setLoggingDirectory(&LogDir); m_pIHandler->setLoggingPriority(&Priority); Ret = m_pIHandler->processITOC( &Template, &Mainframe, &Port, &System, &User, &Password, &Timeout, &upArg, &TransID ); If someone could point something out I'd be grateful. Thanks, Matt WinXP Gfw30-Nov-01 2:39 Gfw 30-Nov-01 2:39  I have a COM object that returns a string to the calling program. It works perfectly under Win95(a) to Win2000. Under WinXP pro, it crashes in oleauto32 if returned as a BSTR, but passes successfully if passed as a safearray. Any ideas? Thanks. How to version an ActiveX dll? David Stranz29-Nov-01 13:19 David Stranz 29-Nov-01 13:19  We have an ActiveX DLL containing both full controls and simple objects, implemented in C++ / ATL. We've updated the library, and want to assign a new version number (say 2, instead of 1). If we edit the RGS and IDL files to reflect the new version number, our users find that the full controls aren't instantiated unless the registry contains the -old- version keys. When a VB project using the controls is opened, it recognizes that an updated version has been registered (asks if you want to update the project), but then can't instantiate the full controls. There is no problem with simple controls, since there is no version number info for them in their registry entries. The problem is only exhibited with full controls. What are we doing wrong? We've searched everywhere we can think of in MSDN and elsewhere for how to do this, but can't find any info. If someone can either answer or point us to documentation, we'd be greatly appreciative. David Stranz ActiveX & Threads...gettin' Funky - Check this Out. Tim Rymer28-Nov-01 11:29 Tim Rymer 28-Nov-01 11:29  I've got this ActiveX Object (made w/ VC++6.0), it creates a thread (so i can have multiple running at the same time), but it also fires events to my Visual Basic App. With me creating threads cause problems for those events trying to get back to the application? It seems that way. VB seems to crash when i Fire an event. When i use an activex control, does it have its own thread? Can i redirect the thread ID or something like that? It's just being flat out weird. Has anyone had the same trouble before? I set up connection points at the beginning when i made the obj., is there any other settings that i need to have? Even a little bit of help will go a long way for me...Thanks Y'all. ~TIM! SHABBA!! Re: ActiveX & Threads...gettin' Funky - Check this Out. Anders Molin30-Nov-01 23:40 Anders Molin 30-Nov-01 23:40  I need to be Free threaded. If you selected Apartment Threaded when you created the object it will fail. Go into the rgs-file, and check the threading model, it should say "Free" and not "Apartment" or something else... - Anders Money talks, but all mine ever says is "Goodbye!" Re: ActiveX & Threads...gettin' Funky - Check this Out. Ali Issa6-Dec-01 3:34 Ali Issa 6-Dec-01 3:34  As well as that, you need to initialise it as multithreaded. Do this in your thread function. G.Luck VB Client: can't see inner aggregated COM object interface 28-Nov-01 5:36 28-Nov-01 5:36  Use COM aggregation: OuterObject ICar, inner aggregated object IVehicle. Have a VB scripting client. When I create the (outer) car object, IntelliSense only shows me the methods and properties of this one (as in the IDL it is defines as the [default] interface for the coclass. I would expect those of the aggregated IVehicle as well Otherwise one can't know that IVehicle is aggregated and supported by ICar and therefore can be accessed through ICar. The object browser only shows two separate Interfaces and its properties ICar and IVehicle. So where can one see in VB, that ICar also supports the Interface IVehicle? Passing SAFEARRAYS through COM events Rick Dangerous28-Nov-01 2:07 Rick Dangerous 28-Nov-01 2:07  Hi, I'm using ATL and have written an event that passes a SAFEARRAY (of doubles) back to the client as one of its parameters In the IDL file I've declared this as: [id(2), helpstring("method SpoilValuesReadyEvent")] HRESULT TFASpoilsReadyEvent(SAFEARRAY(double)* a, double b, double c); producing: HRESULT Fire_TFASpoilsReadyEvent(SAFEARRAY * * a, DOUBLE b, DOUBLE c) etc... in the proxy file. I'm testing the code from a VB client. The client produces: Private Sub test_TFASpoilsReadyEvent(a() As Double, ByVal b As Double, ByVal c As Double) This all seems to be OK. However, when I fire the event, it is not caught by the client. Is there any reason for this apart from probable incompetence ? Re: Passing SAFEARRAYS through COM events Rashid Thadha4-Dec-01 10:39 Rashid Thadha 4-Dec-01 10:39  Why don't you catch the error and get a error description of the failure, this way we might be able to help you ?

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