Re: ActiveX - COM - for Excel Application control - COM Discussion Boards

QueryInterface -- How come this code doesn't work?

Popeye Doyle Murray5-Aug-03 4:16

5-Aug-03 4:16

Here is the code:

// this line gets a valid ADO database connection object
_ConnectionPtr pConnection = m_AdoDatabase.GetActiveConnection();


// Now I will get a pUknown pointing to the database connection
IUnknown* pUnk;

// this is successful
HRESULT hr = pConnection->QueryInterface(IID_IDispatch, (void**) &pUnk);


// Now I will attempt to get an ADO connection object from pUnknown
_ConnectionPtr pConnection2;

// this line fails
hr = pConnection->QueryInterface(__uuidof(Connection), (void**) &pConnection2);

if (FAILED(hr))
{
 // this is where the failure is!
 // hr is returned with a value E_NOINTERFACE
  TRACE("Failed to get pointer the second time.\n");
  TRACE("Error:  %s\n\n", GetComError(hr));
}

Shouldn't I be able to go from an ADO Connection object, to IUnknown, and then back again? How do I get back my ADO Connection from IUnkown?

Re: QueryInterface -- How come this code doesn't work?

Stephane Rodriguez.5-Aug-03 5:49

Stephane Rodriguez.

5-Aug-03 5:49

Haven't checked, but may be __uuidof(Connection) returns the CLSID of the Connection object, while what is expected in queryinterface() is the IID of the interface.

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Re: QueryInterface -- How come this code doesn't work?

geo_m5-Aug-03 22:26

geo_m

5-Aug-03 22:26

right!

Re: QueryInterface -- How come this code doesn't work?

Steve S5-Aug-03 23:20

Steve S

5-Aug-03 23:20

And as an aside, you're not asking for IUnknown in the first QueryInterface, but IDispatch. In the case you have, both should work, of course...

Steve S
[This signature space available for rent]

Re: QueryInterface -- How come this code doesn't work?

Popeye Doyle Murray6-Aug-03 2:29

Popeye Doyle Murray

6-Aug-03 2:29

So how do I get the IID?

Re: QueryInterface -- How come this code doesn't work?

Stephane Rodriguez.6-Aug-03 3:40

Stephane Rodriguez.

6-Aug-03 3:40

I believe either __uuidof(_Connection) or __uuidof(_ConnectionPtr) is better.

Make sure to check that the return IID is non-NULL by the way.

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ActiveX - COM - for Excel Application control

jauss4-Aug-03 23:20

jauss

4-Aug-03 23:20

Hi,

I'm trying to export data to Excel from a C++ Application.
For now, i didn't find any documentation to do this using VC++ Frown | :(

My goal is to export data that user will be able to run Macro on it, made changes or do what ever they want, and then, get back the data to my application.

for now, i've been able to :
launch execl with activex control,
create a workbook,
create a worksheet.

But i cant find how to change name of worksheet, how to access cells...
there a lot of property that i don't know how to change Frown | :(

In my application, I have pointer to my object that i've created with activex controls (excel.application, Workbooks, Worksheet). but i don't know how to access an existing worksheet, or to change data in cells... Frown | :(

if somebody have any good documentation, or some exemples, it will be very usefull.

Please, help !

Jauss

Re: ActiveX - COM - for Excel Application control

Steve S4-Aug-03 23:26

Steve S

4-Aug-03 23:26

To do this, you really need to learn VB! (OK, calm down, just kidding...)
There is a lot of information on the Excel Object Model, primarily aimed at VB programmers. What you need to remember is
(a) VB object is an interface, as far as you're concerned.
(b) Many methods take optional parameters (which you have to pass, but you can say they're not known)
(c) Check for errors at every opportunity.
(d) everything is done using methods, rather than directly accessing members (standard COM rules apply)

There is more helpful information in the MSDN Knowledge base, a search for "EXCEL" and "Automation" should get you some results you can work with.

By using the Workbooks "open" method, you can open an existing workbook (ie XLS file), and then by using that workbook object, you can get from its Worksheets collection, a specific worksheet; you can then get a range of cells from that object, and set or read values using methods.

Hope this is some help.

Steve S
[This signature space available for rent]

Re: ActiveX - COM - for Excel Application control

Stephane Rodriguez.4-Aug-03 23:48

Stephane Rodriguez.

4-Aug-03 23:48

jauss wrote:
if somebody have any good documentation, or some exemples, it will be very usefull.

Why don't you just record a macro in Excel, and then lurk the resulting VB code?

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Re: ActiveX - COM - for Excel Application control

jauss5-Aug-03 1:44

jauss

5-Aug-03 1:44

Stephane Rodriguez. wrote:
Why don't you just record a macro in Excel, and then lurk the resulting VB code?

cause Data are used in a VC++ application, and some customers need to use their own excel macro on those data. That's why it would be great to export those data to excel, and then to retreive the new data.

Re: ActiveX - COM - for Excel Application control

Stephane Rodriguez.5-Aug-03 1:50

Stephane Rodriguez.

5-Aug-03 1:50

I think we don't understand each other well. If you record a macro with Excel, it produces automation code. You can then convert this automation code using C++ syntax to reflect just that.
Converting it is a breeze. What you need is to import the Excel type-library (#import statement), and then the Excel objet model is available to you.

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ATL Language support

Ahmed Birry4-Aug-03 12:13

Ahmed Birry

4-Aug-03 12:13

Hello all
i am new at this, and i have a small quistion about ATL language support for arabic !!!
i am facing some problems with having the arabic flow from right to left, so i cant read it clearly....

is this can be solved ??

if any body knows how to solve that... please send me an email on a.elbirry@lme.tv

thank you so much

Big Grin | :-D

property or method ?

Brian van der Beek3-Aug-03 23:48

Brian van der Beek

3-Aug-03 23:48

I'm working on active scripting (vb-script) support in my application, so my application must support some COM objects. I familliar with COM but relatively new to dispatch interfaces and vb-script. Hence, I'm wondering whether I should expose an interface of a child/sub object via a propery or via a method.
Is there a criteria for using properties / methods?

So for example, should I do this:

Dim module<br />
Set module = modules.module("<name>")

or this:

Dim module<br />
Set module = modules.GetModule("<name>")

I come from China,Who can help me?

yzq_66663-Aug-03 22:39

yzq_6666

3-Aug-03 22:39

I created a COM by pb,i invoked it in WinForm ,it worked well!
But,when i invoked it in Web Services,throw a "System.NullReferenceException" Exception!

Any help would be greatly appreciated!
Thankx!!!

Is it possible to expose a VB 6 Form object type from an C++-made COM Server?

emoscosocam2-Aug-03 12:29

emoscosocam

2-Aug-03 12:29

Hello!

I know that a Visual Basic 6 in-process COM Server can create and give away a reference to a Form (a private type) like this:

' From Class MyComponent.FormCreator
Public Function CreateForm as Object
Set CreateForm = New frmMyForm
End Function

So, a VB client could use an object of type MyComponent.FormCreator to access an instance of frmMyForm:

' Client code
Dim objFormCreator As New MyComponent.FormCreator
Dim objForm as Form

Set objForm = objFormCreator.CreateForm
Set objFormCreator = Nothing ' I do not need this object anymore
objForm.Show ' I use the provided Form

What I would like to know if it is possible to make a C++ COM Server that behaves just like MyComponent.FormCreator. Can I expose my own Form object type that mimics exactly a VB 6 Form?

Thank you very much.

ATL Registration in win98

zxb888888881-Aug-03 23:54

zxb88888888

1-Aug-03 23:54

I'm trying to register an atl com object.
The self-registration succeeds in windows NT but not in win98.

iesharp.81630.com

sharedpropertygroup

Pablo751-Aug-03 3:34

Pablo75

1-Aug-03 3:34

Has anyone used the 'sharedpropertygroup' stuff avaiable in com+ ????

thanks in advance...

Pablo75

Every client call COM+ Server,Server create a new process for it?

doisy31-Jul-03 21:02

doisy

31-Jul-03 21:02

In Windows DNA Architacture, three layer,
Every client call COM+ Server,Server create a new process
for this client?
After this client want to create a com object,
a thread in which com object is run is in that process?
-----------------------------------------

Is the above right? Eek! | :eek:

TIA

Hello everyone

what is difference at COM and DLL?

yanshiqi31-Jul-03 16:01

yanshiqi

31-Jul-03 16:01

Hello everyone

how to access dll from remote machine

sumeetkoshal30-Jul-03 21:10

sumeetkoshal

30-Jul-03 21:10

Hi all,
Can anybody help me about how to access dll from remote machine. I have used ATL AppWizard to develop dll component.
But when i try to call CoCreateInstanceEx(...)
I get the following error message...
"Class Not Registered"

Please help me as soon as possible...

Re: how to access dll from remote machine

valikac31-Jul-03 6:11

valikac

31-Jul-03 6:11

Did you register the COM server on the remove system?

Kuphryn

Re: how to access dll from remote machine

MartinOrtiz31-Jul-03 12:18

MartinOrtiz

31-Jul-03 12:18

This can only be done via DCOM, are you using DCOM? You have to register control via DCOM...I forget the exact procedure offhand.

Plug-in for MS Outlook

Atif Bashir30-Jul-03 16:58

Atif Bashir

30-Jul-03 16:58

I'm student. I've to make a plug-in for MS Outlook. This plug-in will take a particular date, and will delete all the attchments of the e-mails which are older than that specific date.
Kindly guide me for the task. Provide/guide me some sample code if possible. I'll be very grateful to you.
Waiting for your kind response.
Atif

Watch Your Thoughts for they will become your actions.
Watch Your Actions for they will become your habits.
Watch Your Habits for they will become your beliefs.
Watch Your Beliefs for they will determine your destiny.

Asyncrous Callbacks with Connection Points

Giles30-Jul-03 7:22

Giles

30-Jul-03 7:22

I need to put together an ATL COM object making use of connection points to fire Events for a VB client app.

The problem is the Events will need to be fired asyncrously as when I call a particular method it goes of and creates a worker thread. I need to fire events from the worker thread multipe times back to the VB client, problem is that its now in another apartment as far as the origional thread is concerned, so COM will get upset if I user the interface pointer straight off.

From what I can tell it looks like I need to enlist the help of CoMarshalInterThreadInterfaceInStream. Does anyone have any pointers on a problem like this. Its basiclly real time data to a VB client.

As an aside, I know for Excel you can use DDE (tres old) or RTD for a higher though put in Excel XP, but not interested in this yet.

"Je pense, donc je mange." - Rene Descartes 1689 - Just before his mother put his tea on the table.

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Re: Asyncrous Callbacks with Connection Points

Giles30-Jul-03 11:51

Giles

30-Jul-03 11:51

Seems like I found something : http://support.microsoft.com/default.aspx?scid=http://support.microsoft.com:80/support/kb/articles/Q280/5/12.ASP&NoWebContent=1[^]

"Je pense, donc je mange." - Rene Descartes 1689 - Just before his mother put his tea on the table.

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Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.