COM Discussion Boards

Vi227-Jun-03 1:24

27-Jun-03 1:24

You should provide the path where oaidl.idl is placed.

PS
You can include your IDL-file to any your Studio project (temporary) or make the small project for this.

And use Settings... for IDL-file to set necessary options. And compile it.

With best wishes,
Vita

Problem in passing structure pointer via Interface

mpb24-Jun-03 20:48

mpb

24-Jun-03 20:48

Hi,

I have created COM EXE server and it has lot of structures in it. I have defined all the structures in IDL file. Now I am developing one method which passed the Structure data to client through structure pointer in the method. Only this method in not working. Other methods, which passes BSTR are working OK. What is the problem ?

Shall I need marshalling here? I gone through lot of material but I am not able to find sample code for marshalling. Can some body help me in this regard also ?

Regards,
MP

Re: Problem in passing structure pointer via Interface

Aravinthan25-Jun-03 3:03

Aravinthan

25-Jun-03 3:03

Create your proxies again using nmake.exe utility.. it shall work fine..

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Re: Problem in passing structure pointer via Interface

mpb29-Jun-03 19:01

mpb

29-Jun-03 19:01

The easy way I found is to pass the data using IStream interface. At server side, allocate global memmory using CreateStreamOnHGlobal and copy the strcture to it.
Now you can read the allocated strcture from client.

MP

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SetProperty returns "this property is read-only"

Lynnzi24-Jun-03 14:16

Lynnzi

24-Jun-03 14:16

My program has been attached an ocx file from out-resources. When i try to invoke a method, SetServer (which simply calls SetProperty), provided by the ocx, it returns an error "this property is read-only". The similar thing occrs to GetServer(), which returns "this property is write-only".

The guy who provides the ocx claims her ocx works okay.

Any help is appreciated. Thanks in advance.

InternalGetText() issue

Marion2824-Jun-03 4:45

Marion28

24-Jun-03 4:45

Hi all you gurus out there,

I've got a problem with an ActiveX control I wrote. Its a butotn that uses InternalGetText to display text on a button. When I embed the control in a VC6 app the initial caption displayed is correct, but when I chose to change the text again using the controls property page the caption reverts back to the original caption entered using the same property page. I can sucessfully change the caption programmatically using the controls SetCaption stock property later.

Any ideas why this is? Could it be a problem with the controls persistence data?

OLE mini server problem

acosmin23-Jun-03 21:32

acosmin

23-Jun-03 21:32

I developed an OLE mini server using VC++6. Everything works fine (both release and debug) as long as I insert the object manualy through the Insert Object dialog of MS Excel 2000. When I've tried to insert it from a VB AddIn for Excel it draws the frame but the interior of the rectangle remains transparent (the object is created but the container image of it isn't updated). It seems that when I insert from VB the OnGetExtent event it is not triggered (in the manualy case it is). How can I fix it? (I'll try to trigger the OnGetExtent through a method exposed by my object.) Here is a sample of how I try to insert the object from VB:

Dim obj as OLEObject

set obj = XLInstance.Sheets(ActiveSheet.Name).OLEObjects.Add (ClassType:="MyChart.Chart") Dead | X|

Thanx in advance...

Inproc Server in a Surrogate Process

Anonymous23-Jun-03 18:32

Anonymous

23-Jun-03 18:32

Hello, I'm having a problem obtaining an interface pointer (ICreateCar*) on an inproc server that is hosted in dllhost.exe and am unsure if I am overlooking something. Funny as it may seem, if I use the CLSCTX_INPROC_SERVER in the CoCreateInstance or CoGetClassObject call it's successful and I am able to use the requested interface pointer. If I use CLSCTX_LOCAL_SERVER and check the HRESULT after the CreateInstance call has returned the return value is "-2147221163" (Interface not Registered). I have stepped through the code with the Visual C++ Debugger and I'm finding that when I call CreateInstance on a class factory pointer, CreateInstance is able to obtain a valid interface pointer through the QueryInterface call. The HRESULT that is returned from this QueryInterface call is the value that is returned from CreateInstance (in this case it's 0). When I check the HRESULT that is returned from CreateInstance it's not the same value that was returned from the QueryInterface call that was performed in CreateInstance.

Please help, what am I doing wrong?

Thank you.

Client code

<code>	
CoInitialize(NULL);
HRESULT hr;
IClassFactory* pCF = NULL;
ICreateCar* pCreateCar = NULL;

hr = CoGetClassObject(CLSID_CoCar, CLSCTX_LOCAL_SERVER, NULL, IID_IClassFactory, (void**)&pCF);
if (SUCCEEDED(hr))
{		
   hr = pCF->CreateInstance(NULL, IID_ICreateCar, (void**)&pCreateCar);
   pCF->Release();
   if (SUCCEEDED(hr))
   {
      pCreateCar->SetMaxSpeed(100);			
   }
}

</code>

CreateInstance

<code>
STDMETHODIMP CoCarFactory::CreateInstance(IUnknown* pIUnk, REFIID riid, void** ppvObject)
{
   if (pIUnk != NULL)
   {
      return CLASS_E_NOAGGREGATION;
   }
   CoCar* pCoCarObj =  NULL;
   HRESULT hr;
   pCoCarObj = new CoCar();
   hr = pCoCarObj->QueryInterface(riid, ppvObject);
   if (FAILED(hr))
   {
      delete pCoCarObj;
   }
   return hr;
}
</code>

Re: Inproc Server in a Surrogate Process

Vi224-Jun-03 18:35

Vi2

24-Jun-03 18:35

Q: Please help, what am I doing wrong?

A: IMHO, you forgot the marshalling code (proxy/stub DLL) for your interface.

With best wishes,
Vita

Re: Inproc Server in a Surrogate Process

Anonymous25-Jun-03 11:14

Anonymous

25-Jun-03 11:14

Thanks for your help! I did find my problem. The interfaces were not marked with the [oleautomation] attribute. I also did not have the correct information in the system registry (HKCR\Interfaces). I used LoadTypeLibEx to automatically load this information into the system registry.

Thanks again for pointing me in the right direction. Smile | :)

events fired by Internet Explorer

shai197423-Jun-03 11:18

shai1974

23-Jun-03 11:18

Hi,
It may be a stupid question but i am brand new in this area and knows practically nothing.

I am trying to reuse code (implements a band) in order to capture the post data from a web page (that is posted by IE) and send it to my server.
I am trying to use:
Invoke(DISPID dispIdMember, REFIID riid, LCID lcid, WORD wFlags,
DISPPARAMS* pDispParams, VARIANT* pVarResult,
EXCEPINFO* pExcepInfo, UINT* puArgErr)

pDispParams->rgvarg[2] in case : DISPID_BEFORENAVIGATE2 to access the post data but always fail (it is empty or i am doing something wrong to get it).
I m using c++.

Can anyone help ?
thanks
Frown | :(

Re: events fired by Internet Explorer

Amit Dey26-Jun-03 13:52

Amit Dey

26-Jun-03 13:52

Sometime back I too had a similar question. Got the answer from the MS atl newsgroup but I cannot find that post at the moment. OMG | :OMG:

Hush,hush...
thought I heard you call my name now.

Kula Shaker.

Amit Dey
Latest articles at CP -
Writing Word addins
Office addin

Re: events fired by Internet Explorer

shai197426-Jun-03 13:54

shai1974

26-Jun-03 13:54

I have the post data as a string now, but still fail to post it using Navigate, my server recievs a GET request with no post data:
CComVariant varPost(*pDispParams->rgvarg[2].pvarVal);
varPost.ChangeType(VT_BSTR);
LPCSTR lpszPost = (LPCSTR)varPost.bstrVal;
string post_str(lpszPost);
if(strlen(lpszPost))
{
if( (post_str.find("city1") != npos && post_str.find("citd1") != npos &&
post_str.find("time1") != npos && post_str.find("date1") != npos &&
post_str.find("time2") != npos && post_str.find("date2") != npos)
||
(post_str.find("sector1_o") != npos && post_str.find("sector1_d") != npos))
{
string post_url(FC + travel_mate_url);
m_spWebBrowser2->Navigate(CComBSTR(post_url.c_str()), &vtEmpty, &vtEmpty, &varPost, &vtEmpty);
VARIANT vtBandGUID, vtShow;
vtBandGUID.vt = VT_BSTR;
vtBandGUID.bstrVal = SysAllocString(OLESTR("{BE8D0059-D24D-4919-B76F-99F4A2203647}"));
vtShow.vt = VT_BOOL;
vtShow.boolVal = true;
m_spWebBrowser2->ShowBrowserBar(&vtBandGUID, &vtShow, 0);
SysFreeString(vtBandGUID.bstrVal);
}
}

Registering a class

tessierjf23-Jun-03 4:37

tessierjf

23-Jun-03 4:37

I installed the Windows SDK on machine A. I compile my stuff on machine B specifying the include and lib search path on machine A. Everything compiles and links fine since it finds all the .h and .lib in the search path on machine A. My problem is at runtime. When I run the code CoCreateInstance returns "Class not registered". I understand that all classes have been registered on machine A and machine B is not aware of classes I try to create on machine B. So here's the question: How do I register a CoClass contained in a .lib without installing the whole SDK. I'd also like to avoid #importing the nor "LoadingLibrary". To give you a bit more info about this, the class I try to create an instance of is IID_IXMLDOMDocument2 from the msxml2.lib. Anyone have an idea?

Thanks

Jean-Francois !

test container crashes

safee ullah22-Jun-03 21:16

safee ullah

22-Jun-03 21:16

hi there
i wanted some help inorder to avoid a crash of the test container.After i insert my control into the test container, the container crashes after an exact "Certain" amount of time...always..
i mean when i insert the control, the control crashes after about 30 seconds..what possible problems can be there???
ne suggestions will be most valued..

thanks and regards

safee

Re: test container crashes

Marion2827-Jun-03 4:42

Marion28

27-Jun-03 4:42

More specifics would help. What does your control do? Can you send source code?

COM Question

Nick Parker22-Jun-03 4:39

Nick Parker

22-Jun-03 4:39

I have been reading Visual C++.NET by George Shepherd and I ran into something that didn't quite jive with me. Look at the following first:

struct CSpaceship : IMotion. IDisplay
{
ULONG m_cRef;
//...

HRESULT QueryInterface(REFIID riid, 
                       void** ppv);
  ULONG AddRef()
  {
     return InterlockedIncrement(&m_cRef);
  }

  ULONG Release()
  {
     ULONG cRef = InterlockedIncrement(&m_cRef);
     if(cRef == 0)
     {
         delete this;
         return 0;
     }
     else
         return m_cRef;
  }

//...
};

Possibly this isn't a complete implementation of Release(); but shouldn't m_cRef be decremented somewhere in Release();? I can't see how the InterlockedIncrement(); could do this because it is being called in AddRef(); as well as in the Release(); method.

-Nick Parker

Re: COM Question

valikac22-Jun-03 7:32

valikac

22-Jun-03 7:32

Interesting. Maybe it it is an error. Otherwise, the server is testing to make sure the client has released all pointers and m_cRef is actually at zero. One situation is multithreading.

Kuphryn

Re: COM Question

Aravinthan25-Jun-03 3:08

Aravinthan

25-Jun-03 3:08

I think it might be a typo mistake.. i feel it should be interlockeddecrement() function called instead of the increment!! for otherwise.. the component will never die..! or the cref==0 will never happen! as each time the value will always increase!

Aravinthan

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How can my ActiveX control get the data of the file which locates on the server?

stanley guan21-Jun-03 1:18

stanley guan

21-Jun-03 1:18

The activeX has to read the information of a file which locates on the sever.
I notify the activeX the file URL(such as "http://10.0.10.10/test.i3d"), how can the activeX control download the specified file?

stanley

Re: How can my ActiveX control get the data of the file which locates on the server?

valikac21-Jun-03 7:41

valikac

21-Jun-03 7:41

One solution is winsock.

Kuphryn

COM interop in .NET

slnarasimhan19-Jun-03 22:28

slnarasimhan

19-Jun-03 22:28

Hi,
I need to access the native COM provided by adobe for manipulating PDF's in my .NET application. Once i added a reference to it through the .NET IDE, i am not able to create an object as all the members within the namespace are interfaces. Am i doing something wrong?? If not can somebody suggest a work around for this???

Regards,
SLN

Third party program library method calls invocation

yeeck19-Jun-03 21:14

yeeck

19-Jun-03 21:14

Hi,

I am trying to integrate (initiate calls) to a third party software application sitting on another box (BOX B) which only provides a set of function calls exported from its own dynamic link library (.dll). The vendor for the third party application sitting on another box I'm trying to integrate to doesn't want to do any development effort, other than to provide the .dll file. They provided interface examples for VB, C/C++, and MicroFocus Cobol. However, these codes will only work if the it is sitting in the same box (BOX B) as that app.

On my part, the integration software (in BOX A) I'm using will be able to initiate to invoke DCOM objects. However, I'm completely at a lost as to how to create a DCOM object which is able to invoke the dll on BOX B. Can anyone advise and help me in this matter?

Regards,
KY

COM+ Error

Aky18-Jun-03 23:31

Aky

18-Jun-03 23:31

Im getting a COM+ error which is like

The system has called a custom component and that component has failed and generated an exception. This indicates a problem with the custom component. Notify the developer of this component that a failure has occurred and provide them with the information below.
Component Prog ID:
Server Application ID: {5C36819D-0094-454E-B9D2-C5B9C8FA34CE}
Server Application Name: TransactOnline
The serious nature of this error has caused the process to terminate.
Exception: C0000005
Address: 0x779D9256
Call Stack:
OLEAUT32!SysFreeString + 0x46
RPCRT4!NdrServerInitialize + 0x288
RPCRT4!NdrStubCall2 + 0x570
RPCRT4!CStdStubBuffer_Invoke + 0xC5
OLEAUT32!UserEXCEPINFO_free_local + 0x2114
+ 0xFFFFFFF7
+ 0x8820B0A8
------------------------------------------------
I have found out the that error to a particular structure which is

typedef struct XXXX
{
BSTR A_account;
BSTR B_Date;
BSTR C_Date;
BSTR D_Date;
} YYYY

In Sysfreestring(YYYY.B_Date),it is failing and giving errors.

I have initialised this structure through VB and passed to COM.

Moreover,when i build this on my machine (all params and environments are same), this works good.
The only difference between the "original Build machine" and my machine is i have Visual Studio SP5.
Any suggestions?..

Re: COM+ Error

Steve S23-Jun-03 21:50

Steve S

23-Jun-03 21:50

Sounds like you need to dump out what the values (and addresses) in the structure are. The error you're getting sounds like a BSTR being freed twice, or similar.

Steve S
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