COM Discussion Boards

Re: for people with experience with ActiveX Controls..

7-Aug-03 6:09

The simplest way to solve the issue is to start a debug session for your ActiveX component by first of all pointing the executable to "ActiveX test container" in your Project settings \ Debug Tab.
If you put a breakpoint in a destructor somehow, the session will halt there and hopefully it will be possible to isolate the issue.

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safee ullah7-Aug-03 23:16

safee ullah

7-Aug-03 23:16

yup got it..
thanks a lot Smile | :)

One more thing if u may have time..how can i check for memory leaks in my application??

ne ideaz!

thanks
kindest regards
safee

Re: for people with experience with ActiveX Controls..

Stephane Rodriguez.7-Aug-03 23:25

Re: for people with experience with ActiveX Controls..

7-Aug-03 23:25

safeeullah wrote:
One more thing if u may have time..how can i check for memory leaks in my application??

When the debug session ends, it shows all leaks in the console window. If you are using MFC, you'll have plenty of details and will be able to double-click on the messages to reach the actual code being guilty. If you are not using MFC, you can instrumentalize your code by either of those :
- lookup this article[^] on CodeProject
- buy a commercial product like BoundsChecker (from Numega).

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safee ullah8-Aug-03 0:17

safee ullah

8-Aug-03 0:17

thanks stephane..
one last thing Smile | :)

i solved the crashing issue as well as the leak checking..
then i build my control in release mode..

when i built it in release mode, my spreadsheet stopped taking in data entries to cells..

ne information on this?

thanks again Wink | ;)

Re: for people with experience with ActiveX Controls..

Stephane Rodriguez.8-Aug-03 0:30

calling vc6 dll from vb6 activex dll

8-Aug-03 0:30

safeeullah wrote:
when i built it in release mode, my spreadsheet stopped taking in data entries to cells..

1) Check out you don't have significant code in a

#ifdef _DEBUG
...
#endif

section. Because in release mode, no code would be generated.

2) If the debug mode works fine, and the release mode doesn't, it's usually because the code is weak. There is a probably a bad use of pointers somewhere.

- check out the console window for all "exception errors" that might be produced by Excel (or any other ActiveX host).
- build the release mode with "Debug Info". And check the ".pdb" box. Doing so, you can put a breakpoint even in release mode.
- Add a DebugBreak() statement in your code. This allows to halt the code, start a session, and watch variables, etc. To have this to work properly, it's best to generate a release version with all the debug info (see above).
- add a few message boxes in your code, and watch them. That's the most primitive way of solving issues, but sometimes it's enough!

Good luck!

And if you are to go on with debugging, crash handlers, etc. don't hesitate to buy this book[^].

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patwilliams6-Aug-03 5:53

patwilliams

6-Aug-03 5:53

After reading several boards, I'm close but no cigar. I have an existing C++ app that calls my vc6 dll which calls a vb6 dll. That seems to work fine except when I try to call a function in the vc dll from the vb dll. It works fine if I call the c++ dll from a vb exe. For this test, the calling vc app does a simple call to fakePlugIn().

The vc dll:

#include "stdafx.h"
#import "testvb.dll"
using namespace testvb;

extern "C" __declspec(dllexport) fakePlugIn()
{
HRESULT hresult;
CLSID clsid;
_vbdllcls *t;

CoInitialize(NULL); //initialize COM library
hresult=CLSIDFromProgID(OLESTR("testvb.vbdllcls"), &clsid);
hresult=CoCreateInstance(clsid,NULL,CLSCTX_INPROC_SERVER,__uuidof(_vbdllcls),(LPVOID *) &t);
if(FAILED(hresult))
{
AfxMessageBox("Creation Failed");
return false;
}
t->InVbDll("string to vb dll"); //call the vb dll
t->Release();
CoUninitialize();
return true;
}

extern "C" void __declspec(dllexport) Callback(void)
{
AfxMessageBox("in callback");
}

The vb code:

Public Declare Function Callback Lib "testcpp.dll" () 'this is in a module

Public Function InVbDll(ByVal s As String) As Long 'this is in class vbdllcls
MsgBox s
Callback
End Function

With Callback defined as __declspec(dllexport), the message box in Callback gets executed but then I get a runtime error: Run-Time Check Failure #0 - The value of ESP was not properly saved across a function call.

OK so I tried __stdcall instead. Then I don't make it to the Callback and get a runtime error:

First-chance exception at 0x77e73887 in cppshell.exe: 0xC000008F: Floating-point inexact result.
First-chance exception at 0x77e73887 in cppshell.exe: Microsoft C++ exception: _com_error @ 0x0012fbac.

I've tried various combinations as well with the same result. Ultimately, I'd like to pass strings into and possibly out of Callback, but one step at a time.

Any light you could shed on this would be appreciated!

Using MS Web Browser ActiveX Control

Douglas Troy5-Aug-03 5:11

Douglas Troy

5-Aug-03 5:11

I am hosting the Web Browser control in an application, and am setting the initial nav URL to a local directory. I would like to default the "View" to Thumbnails, but I cannot find where the View Type property is exposed.

Does anyone know how I can get access to this property and set it?

I have checked all the exposed interfaces for this control and did not see where this might be exposed as a method. The IWebBrowser2 interface exposes two Methods "GetProperty and PutProperty", not sure I could use these, mainly because I would have to know the property to get/put.

Any help would be great!

Thanx,

D.

Stephane Rodriguez.6-Aug-03 10:53

6-Aug-03 10:53

Douglas Troy wrote:
I am hosting the Web Browser control in an application, and am setting the initial nav URL to a local directory. I would like to default the "View" to Thumbnails, but I cannot find where the View Type property is exposed.

There is no relationship, or at least I am not aware of it, between the web browser control which can be used to navigate web pages, and the windows explorer thumbnail view.
More to the point, where the web browser is used is for image preview when windows explorer is in web page mode (not in thumbnail view) : in this mode, windows explorer reads and executes the html code described in <windows dir> \ folder.htt. By default this code uses an ActiveX control to build a picture preview from the current file selection.

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Douglas Troy7-Aug-03 5:57

Douglas Troy

7-Aug-03 5:57

If your application hosts the Web Browser control and you point your initial nav location to a local drive, it will display a list of files (like standard Windows Explorer) ... I was hoping that I could somehow drill down into the shell to hook the view type and set it by default to Thumbnail.

I'll mess with the Folder.htt, and see if perhaps we can't just dump that file into our images directory and get it to automatically thumb that folder.

Thanks,

D.

Stephane Rodriguez.7-Aug-03 6:07

7-Aug-03 6:07

HRESULT IShellView::CreateViewWindow(
IShellView *psvPrevious,
FOLDERSETTINGS *pfs,
IShellBrowser *psb,
RECT *prcView,
HWND *phWnd
);

where

typedef struct {
UINT ViewMode;
UINT fFlags;
} FOLDERSETTINGS, *LPFOLDERSETTINGS;

and ViewMode is :

typedef enum {
FVM_FIRST = 1,
FVM_ICON = 1,
FVM_SMALLICON = 2,
FVM_LIST = 3,
FVM_DETAILS = 4,
FVM_THUMBNAIL = 5,
FVM_TILE = 6,
FVM_THUMBSTRIP = 7,
FVM_LAST = 7
} FOLDERVIEWMODE;

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

Douglas Troy7-Aug-03 7:03

Douglas Troy

7-Aug-03 7:03

Excellent! I must be blind, because I swear I checked my Platform SDK Docs IShellView and did not see reference to the File Folder struct you've provided here; I'll check again.

Thank you for the information, this is a big help,

D.

Popeye Doyle Murray5-Aug-03 4:16

Popeye Doyle Murray

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

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

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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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

ActiveX - COM - for Excel Application control

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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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

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]

Stephane Rodriguez.4-Aug-03 23:48

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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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.

Stephane Rodriguez.5-Aug-03 1:50