Re: Using C# and COM to connect to a Server - COM Discussion Boards

Christian Bayer6-Oct-08 6:51

6-Oct-08 6:51

Hello!

I am working on a C# COM-Server and a C++ COM client app. The client in fact
loads a dll-plugin containing the COM client in a class that acts as a com
event reciever:

extern "C"
__declspec(dllexport)
int ndofInit();

extern "C"
__declspec(dllexport)
void* ndofOpen(void* wnd);

extern "C"
__declspec(dllexport)
void ndofShutdown(void* deviceHandle);

[ event_receiver(com) ]
[ module(type=dll, name="NDOF") ]
class NDOFServer
{
public:
NDOFServer() {}
virtual ~NDOFServer();

...
}

Everytime I start the client I get the following error:

Debug Assertion failed!
Program ...
File: C:\Programme\Microsoft Visual Studio 8\VC\atlmfc\include\atlbase.h
Line 2706

Expression _pAtlModule == 0

Clicking Retry and returning to my code reveals that this error occurs when
the constructor of NDOFServer() is called.
The constructor is called this way by the client app:

extern "C"
__declspec(dllexport)
int ndofInit()
{
if (sNdofServer == NULL)
sNdofServer = new NDOFServer();

return 1;
}

This error seems not to occur when the client plugin-DLL is used with
another COM server offering the same classes etc. written in C++ (whose code
I do not know).

I tried to switch some more or less relevant options in the project
properties like:
- MFC usage static/shared/Windows shared
- ATL usage static/shared/none
- minimize CRT usage in ATL yes/no
- CLR support no/CLR

stdafx.h looks like this:

#if defined(_WIN32)
#ifndef WINVER // Allow use of features specific to #define WINVER
0x0501 // Change this to to target other
#endif
#ifndef _WIN32_WINNT // Allow use of features specific to
#define _WIN32_WINNT 0x0501 // (was 0x0501) Change to target other versions
#endif

#ifndef _WIN32_WINDOWS // Allow use of features specific to
#define _WIN32_WINDOWS 0x0410 // Change this to target Windows Me or later.
#endif

#ifndef _WIN32_IE // Allow use of features specific to IE
#define _WIN32_IE 0x0600 // Change this to target other versions of IE.
#endif

#define _ATL_APARTMENT_THREADED
#define _ATL_NO_AUTOMATIC_NAMESPACE
#define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS
#include <atlbase.h>
#include <atlcom.h>

<---->
//#include <atlwin.h>
//#include <atltypes.h>
//#include <atlctl.h>
//#include <atlhost.h>
--> commenting these headers out did neither help nor hurt

using namespace ATL;
#import "progid:AerionInput.Device" embedded_idl no_namespace
#endif //_WIN32

The C# DLL is nothing spectacular and the "main" class(or the first one
being instanciated), which is not instanciated at this time. The COM-visible
interface looks like this:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace AerionInput
{
[
Guid("CB3BF65E-0816-482A-BB11-64AF1E837812"),
InterfaceType(ComInterfaceType.InterfaceIsDual)
]
public interface ISimpleDevice
{
int Type
{
get;
}

IKeyboard Keyboard
{
get;
}

ISensor Sensor
{
get;
}

void Connect();
void Disconnect();
void LoadPreferences(string preferencesName);
}
}

And the AssemblyInfo.cs reads this like:

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
[assembly: AssemblyTitle("TDxInput")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyCompany("n/a")]
[assembly: AssemblyProduct("TDxInput")]
[assembly: AssemblyCopyright("Copyright © n/a 2008")]
[assembly: AssemblyTrademark("")]
[assembly: AssemblyCulture("")]
[assembly: ComVisible(true)]
[assembly: Guid("7858b9e0-5793-4be4-9b53-661d922790d2")]
[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]

I am doing this on Windows 2000 with Visual Studio 2005 Pro latest SP and
.NET 2.0.50727 SP1.

Thanks in advance,
Christian

Runs on Server, not on Workstations

rahvyn133-Oct-08 6:32

rahvyn13

3-Oct-08 6:32

I have a VB.Net COM dll that I created and installed (using regasm) on a server. On this server is an application that calls different code modules based on events. One of those code modules calls the com dll which fires off and does a few things. If this process is kicked off from the server, everything works just fine. However, when the application is run from a workstation, the COM call fails. The workstation calls the code modules that reside on the server, the same ones that the server uses.

So why would the call to the COM object work fine on the Server, but when called through a workstation, to the server, fails out?

The CreateObject statement that creates the com object does not fail, but when called through the workstation, the call to the COM method fails.

Here's an example:

foo = CreateObject("Obj.Class")
result = foo.callMethod

The CreateObject works fine, but the foo.callMethod fails when it is kicked off from a workstation.

Anyone run into something like this before?

Headers created by MIDL, position of DECLSPEC_UUID

Andreas Tondorf1-Oct-08 22:13

Andreas Tondorf

1-Oct-08 22:13

I would like to use the DECLSPEC_UUID and __uuidof operators to identify my record types.
In the IDLs I use constructs like:

typedef 
[ uuid(....) 
, version(1.0)] struct x { 
... 
} x;

Ok now MIDL creates in the header:

typedef DECLSPEC_UUID(....) struct x { 
... 
} x;

But the call of __uuidof(x) is invalid, as the order of DECLSPEC_UUID and struct has to be switched. So why does MIDL create this unusable code??
One possible solution is dropping typedef, but in each sample idl I saw before they allways used typedef with structures. Furthermore it is not possible to use the version-tag without the typedef.

Any Ideas??

How do I pass MySQL connection ID to COM using VC++ 9.0?

Ger Hayden30-Sep-08 7:22

Ger Hayden

30-Sep-08 7:22

How do I pass MySQL connection ID to COM using VC++ 9.0?

At the moment I have to pass the host, username, pwd, and db name to the COM but make a new connnection there. I want to pass the connection ID but I am unable to shoehorn a variable of type MYSQL into an acceptable parameter.

GER

Ger

COM add in for MS Office Outlook?

maui_mike29-Sep-08 20:19

maui_mike

29-Sep-08 20:19

Hi,

I have a VS 6.0 (visual basic) add-in for Outlook that I wrote for Outlook 2002 (XP). It is a useful add in that I wish (or maybe not, LOL) to modify to support Outlook 2003 & 2007. I have Visual Studio 2008 Pro installed along with Office 2003.

Using the VSTO add-in templates, I wanted to create a simple 'Hello' add-in and ensure that it works and then test it on a client install (a machine not running any development tools). At first I thought this would be easy, but find my asking Why is it so difficult to create a simple add-in and have it work. Mad | :mad:

The built-in VSTO addin templates seem to force .NET, which has many pre-requisites and all kinds of stuff.
My first question to the Code Project World, <u>is it better to use templates or create Addin using C++ and COM without .NET? </u>

I did write a simple 'Hello' using C++/COM without .NET, which produces a <i>Clean</i> .dll that registers as add-in. Where the .NET solution has manifest and .NET security policy assembly difficulties. Plus .NET is not required and do not want to force clients to install All this extra Baggage for what should be a simple addin.

Thanks to code found here on CodeProject, I was able to get this far, but am at a crossroad now. I appreciate any comments from the experts.

Aloha, Mike

MMDeviceEnumerator registration problem

punitkumar2629-Sep-08 13:09

punitkumar26

29-Sep-08 13:09

Hi,

I am using CLSID_MMDeviceEnumerator for creating the instance of MMDeviceEnumerator.However,the call CoCreateInstance is failing saying the class is not registered.Upon checking the CLSIDs in the registry,i found that its not there in registry.
What to do?

The below code is taken from MSDN.

// soundcard.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<atlbase.h>

//#include "Winerror.h"
#include "Mmdeviceapi.h"
#include "Functiondiscoverykeys_devpkey.h"
//-----------------------------------------------------------
// This function enumerates all active (plugged in) audio
// rendering endpoint devices. It prints the friendly name
// and endpoint ID string of each endpoint device.
//-----------------------------------------------------------
#define EXIT_ON_ERROR(hres) \
if (FAILED(hres)) { goto Exit; }
#define SAFE_RELEASE(punk) \
if ((punk) != NULL) \
{ (punk)->Release(); (punk) = NULL; }

const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);

void PrintEndpointNames()
{

HRESULT hr = S_OK;
IMMDeviceEnumerator *pEnumerator = NULL;
IMMDeviceCollection *pCollection = NULL;
IMMDevice *pEndpoint = NULL;
IPropertyStore *pProps = NULL;
LPWSTR pwszID = NULL;

hr = CoCreateInstance(
CLSID_MMDeviceEnumerator, NULL,
CLSCTX_INPROC_SERVER, IID_IMMDeviceEnumerator,
(void**)&pEnumerator);
EXIT_ON_ERROR(hr)

hr = pEnumerator->EnumAudioEndpoints(
eRender, DEVICE_STATE_ACTIVE,
&pCollection);
EXIT_ON_ERROR(hr)

UINT count;
hr = pCollection->GetCount(&count);
EXIT_ON_ERROR(hr)

if (count == 0)
{
printf("No endpoints found.\n");
}

// Each loop prints the name of an endpoint device.
for (ULONG i = 0; i < count; i++)
{
// Get pointer to endpoint number i.
hr = pCollection->Item(i, &pEndpoint);
EXIT_ON_ERROR(hr)

// Get the endpoint ID string.
hr = pEndpoint->GetId(&pwszID);
EXIT_ON_ERROR(hr)

hr = pEndpoint->OpenPropertyStore(
STGM_READ, &pProps);
EXIT_ON_ERROR(hr)

PROPVARIANT varName;
// Initialize container for property value.
PropVariantInit(&varName);

// Get the endpoint's friendly-name property.
hr = pProps->GetValue(
PKEY_Device_FriendlyName, &varName);
EXIT_ON_ERROR(hr)

// Print endpoint friendly name and endpoint ID.
printf("Endpoint %d: \"%S\" (%S)\n",
i, varName.pwszVal, pwszID);

CoTaskMemFree(pwszID);
pwszID = NULL;
PropVariantClear(&varName);
SAFE_RELEASE(pProps)
SAFE_RELEASE(pEndpoint)
}
SAFE_RELEASE(pEnumerator)
SAFE_RELEASE(pCollection)
return;

Exit:
printf("Error!\n");
CoTaskMemFree(pwszID);
SAFE_RELEASE(pEnumerator)
SAFE_RELEASE(pCollection)
SAFE_RELEASE(pEndpoint)
SAFE_RELEASE(pProps)
}

int _tmain(int argc, _TCHAR* argv[])
{ HRESULT hr=CoInitialize(NULL);
PrintEndpointNames();
::CoUninitialize();
return 0;
}

Using C# and COM to connect to a Server

SRogers8829-Sep-08 7:44

SRogers88

29-Sep-08 7:44

Hello,

I am trying to find some examples and information on how to add COM to the C# application and connect to a COM server that was created with C++. Any help would be wonderful.

Thanks

Re: Using C# and COM to connect to a Server

alchong8-Oct-08 14:19

alchong

8-Oct-08 14:19

This article may help:

http://www.codeproject.com/KB/cs/usecomappincs.aspx[^]

Get COM pointer to running instance of Yahoo Messenger.

u0m326-Sep-08 7:02

u0m3

26-Sep-08 7:02

Hello.
I was wondering if it is possible to get a COM pointer to a running instance of Yahoo Messenger.
I have tried several methods but got stuck due to the fact that I am kind of a noob when it comes to COM.
The best I managed is to create a instance of Yahoo! Messenger via COM from my app.

In order to run multiple instances of Yahoo! Messenger you need to set<br />
[HKEY_CURRENT_USER\Software\yahoo\pager\Test]<br />
"Plural"=dword:00000001

I apologize if my question is with obvious answer/stupid/dumb.

Thanks in advance.

How to Include MFC Datatypes in IDl ?

narayanagvs25-Sep-08 23:20

narayanagvs

25-Sep-08 23:20

Hi,

I need to pass MFC Class "CStringArray" as Parameter in my exposed method in com component.
When I Compile I get 2 errors

1)#error MFC requires C++ compilation (use a .cpp suffix)
2)command line error MIDL1003 : error returned by the C preprocessor (2)midl

Can Anybody suggest me how to go about it?

Thanks
Satya

Today is a gift, that's why it is called the present.

Extra Chart in OWC11 (ASP)!

marlboroguy5824-Sep-08 1:35

marlboroguy58

24-Sep-08 1:35

Hi,
I m using OWC11 with ASP, Trying to draw simple Bar graph using data from SQL database, i managed to draw the chart but i also have an extra chart(to the right) with it. Please let me know how to get rid of it.

here is the piece of code that does the charting

Set objRS1  = Server.CreateObject("ADODB.Recordset")

            objRS1.Open strSQLStatement, objADODB, 1
            'Response.Write("The value of " & strColName & "=" & objRS1(0))
            set objCSpace = Server.CreateObject("OWC11.ChartSpace")
            'set up chart and properties
            set objChart = objCSpace.Charts.Add(0)
            set objConstants = objCSpace.Constants

            'create a clustered column chart
            objChart.Type = objConstants.chChartTypeColumn3D
            
            
            'add a legend
            objChart.HasLegend = False
            
            'objChart.ShowFilterHeaders = False
            set objCSpace.DataSource = objRS1

            objCSpace.HasMultipleCharts = False
            objCSpace.HasChartSpaceLegend = False
            objCSpace.HasChartSpaceTitle = False
            objCSpace.DisplayFieldButtons = false
            objCSpace.MinorVersion =
            
            'set the data points and categories
            'objChart.SetData objConstants.chDimSeriesNames, 0, "age"
            objChart.SetData objConstants.chDimCategories, 0, "Level"
            objChart.SetData objConstants.chDimValues, 0, "NOF"

            'set up some additional properties
            'add and format the chart title
            objChart.HasTitle = True
            objChart.Title.Caption = "TICS Summary"
            set objFont = objChart.Title.Font
            objFont.Name = "Tahoma"
            objFont.Size = 10
            objFont.Bold = True

            'add and format a title to the category axis
            set objAxis = objChart.Axes(objConstants.chAxisPositionBottom)
            objAxis.HasTitle = True
            objAxis.Title.Caption = "TICS Levels"
            set objFont = objAxis.Title.Font
            objFont.Name = "Tahoma"
            objFont.Size = 8
            objFont.Bold = True

            'add and format a title to the value axis
            set objAxis = objChart.Axes(objConstants.chAxisPositionLeft)
            objAxis.HasTitle = True
            objAxis.Title.Caption = "No. Of Files"
            set objFont = objAxis.Title.Font
            objFont.Name = "Tahoma"
            objFont.Size = 8
            objFont.Bold = True


            'Save the current chart to a GIF file with a temporary
            'filename using the FSO
            set fso = Server.CreateObject("Scripting.FileSystemObject")
            strFileName = fso.GetTempName()
            GifFileName = strFileName
            strFileName = Server.MapPath(".") & "\" & strFileName
            RenName = strFileName
            RenName = replace (RenName, ".tmp", ".gif")
            'Response.Write(GifFileName)
            GifFileName = replace (GifFileName, ".tmp", ".gif")
            objCSpace.ExportPicture RenName, "gif", 800, 400
            'fso.MoveFile strFileName,GifFileName
            Response.Write("<img src=" & GifFileName & ">")
            'Use On Error Resume Next to make sure we eventually delete
            'the temporary GIF file even if something fails in the next
            'couple of functions
            on error resume next

            'The GIF file has been created. Return the contents of the
            'GIF file as binary data using the BinaryFileStream COM object
            set objBinaryFile = Server.CreateObject("BinaryFileStream.Object")
            Response.BinaryWrite objBinaryFile.GetFileBytes(CStr(strFileName))

            'Delete the GIF file since it is no longer needed
            objBinaryFile.DeleteFile CStr(RenName)

            'clear variables
            set objBinaryFile = nothing
            set FSO = nothing
            set objCSpace = nothing
</img>

Please Help!!!

Word Automation

g_dev23-Sep-08 18:37

g_dev

23-Sep-08 18:37

Hello!

My name is Alla. I'w working as a programmer in New Hampshire. I've just started doing Word and Powerpoint Automation (never done before Office Automation). The application I'm working on now creates document-packages,containing one or more Word documents and export these documents to particular locations.
I created Word Application Instance only once at the beginning, so I use this Instance for all documents that I'm going to create for exporting. Everything was fine so far, but when I'm trying to export a huge amount of documents,the following error appears - RPC SERVER UNAVAILABLE and any reference to existing Word Instance throws an error ( it happens when during processing some documents for some reason Range.Paste method throws an exception (RPC server failed)., then I get MS Word warning message and Word trying to recover documents. Immediately after that I get RPC SERVER UNAVAILABLE - means that any access to my Word Instance fails. May be it makes sense to create many Word Application Instances for each document, but we have problem with performance.I tried to send this question to microsoft forums, but nobody responded..Could you, please, help me to solve this problem?

Thank you very much in advance and best regards.
Alla

Re: Word Automation

kattah28-Jan-09 13:03

kattah

28-Jan-09 13:03

Hey How did you resolve this?

Word Automation

g_dev23-Sep-08 18:36

g_dev

23-Sep-08 18:36

vc++ and .net Runtime error

balu1234522-Sep-08 9:15

balu12345

22-Sep-08 9:15

Hi,

My application working fine in the dev environment.But in the testing /production environment
it is not working because that environment has only
windows server 2003
IIS

I have prepared a MSI which will automatically install .net2.0 framework

In my application I have Used some microsoft VC++ dll's also along with .net dll's.

Now Iam getting "RUNTime Error" pop-up screen message as below

" The Application has been terminated in an Unusual Way"

On googling i came to know that some dll's like msvcrt.dll of windows server 2003 has to be changed...But Iam not pretty sure about it..

In Production/test environment there is only framework installed ,but there is no visual studio installed on it.may be due that this error may occur...

So kindly post your suggestions and views to help me

Synchronization concepts.. [modified]

kDevloper21-Sep-08 21:13

kDevloper

21-Sep-08 21:13

Hi,

Need help in Synchronizing Execution of Multiple Threads in VC++, i am new to Multithreading Programming.. Any related book or documents will be useful. Smile | :)

Regards,
KDevloper

modified on Saturday, October 4, 2008 12:25 AM

Re: Synchronization concepts..

John_Adams3-Oct-08 12:47

John_Adams

3-Oct-08 12:47

Hi,

Go through the following article, that will give you some idea about Multithreading programming using Visual Basic.

Article1[^]

Artcle2[^]

Article3[^]

Hope this helps Smile | :)

Regards,
John Adams
ComponentOne LLC

Re: Synchronization concepts..

kDevloper3-Oct-08 18:25

kDevloper

3-Oct-08 18:25

Thanks John, Am sorry to mention that i need Multithreading programming using Visual c++.

Regards,
KDevloper

How to draw sth. on owner flash ole container

61934514220-Sep-08 14:38

619345142

20-Sep-08 14:38

I have already download the sourcecode of Transparent Flash Control
http://www.codeproject.com/KB/COM/flashcontrol.aspx

now I want to draw something on the flash control, I do it like this
OLECONTAINER(void)::Draw(HDC hdcDraw, const RECT *rcDraw, BOOL bErase)
{
HWND hwnd = GetHWND();
HRESULT hr;
RECT r;

IOleObject *lpO = m_lpO;
IViewObject *lpV = m_lpViewObjectEx ? (IViewObject
*)m_lpViewObjectEx : m_lpViewObject;

// if (!m_bTransparent)
{
RECT rTotal;
::GetClientRect(hwnd, &rTotal);
if (lpV)
{
if (!hdcDraw)
{
hdcDraw = ::GetDC(hwnd);
hr = OleDraw(lpV, DVASPECT_CONTENT, hdcDraw, &rTotal);
::ReleaseDC(hwnd, hdcDraw);
}
else
{
hr = OleDraw(lpV, DVASPECT_CONTENT, hdcDraw, &rTotal);
}
}

TextOut(hdcDraw, 0, 0, "test", 4); // <======= do it like this
return;
}

But I find that the text drawn on the hdc will always be covered drawn by flash control
how can I do it?

Dynamic DLL creation

Member 400849215-Sep-08 3:11

Member 4008492

15-Sep-08 3:11

Hi all
I have to Create a DLL dynamically in C#. I dont know how Can i Create it dynamicaaly. Can anyone tell me the solution for this.

Thanks in advance
sri

C++ and COM

bhogavalli suresh14-Sep-08 19:19

bhogavalli suresh

14-Sep-08 19:19

What aspect of the C++ language makes it easily adapted to COM application

Re: C++ and COM

Lim Bio Liong14-Sep-08 21:44

Lim Bio Liong

14-Sep-08 21:44

For VC++'s implementation of C++ : it's the v-table.

- Bio.

Re: C++ and COM

Ju@ncho19-Sep-08 9:57

Ju@ncho

19-Sep-08 9:57

In c++ you got ATL wich is a good way for developing COM objects

Re: C++ and COM

Jagdish Vasani19-Sep-08 21:34

Jagdish Vasani

19-Sep-08 21:34

C++ suport Pointer virtual mechanishm(Vtable),that ascpect will more help to develop COM application with efficent resource uses.

Error loading type library/DLL

Sara1239-Sep-08 0:38

Sara123

9-Sep-08 0:38

I’m using idl file to create COM Type Library,
Here is the idl:

import "oaidl.idl";
import "ocidl.idl";
[
uuid(71050F79-3FC6-4BCA-BC36-A79465500B71),
version(1.0),
helpstring("MyProj 1.0 Type Library")
]
library MyProjLib
{
importlib("stdole32.tlb");
importlib("stdole2.tlb");
importlib("..\Interfaces\Interfaces.tlb");

[
uuid(83BC908B-C13C-4D6A-B290-C97057ACEBC4),
helpstring("MyClass Class")
]
coclass MyClass
{
[default] interface IMyProjMessage;
};
};

In another project, I call the library with:
#import "..\..\MyProj\MyProj.tlb" raw_interfaces_only, raw_native_types, no_namespace, named_guids

Here’s the error I've got:
fatal error C1084: Cannot read type library file: '..\..\MyProj\MyProj.tlb': Error loading type library/DLL.

I am newer for com & activeX controls – can someone help me?

Many thanks,
S

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