C / C++ / MFC

Access to COM methods inside Windows Service ATL

22-Feb-06 8:04

thanks for you quick reply!
i am using LVM_GETNEXTITEM now.

i stumbled over the line "The specified item is itself excluded from the search"
on MSDN, and modified my code so it works with top-down deletion:

iWalk = SendMessage( _hView, LVM_GETNEXTITEM, iWalk - 1, LVNI_SELECTED );

-------------------------------------------
My website: http://www.hartwork.org

cmacgowan22-Feb-06 6:03

cmacgowan

22-Feb-06 6:03

Hi ...

I have written a Windows Service using ATL COM (ATL3 / Visual Studio 6.0). The service works fine, I am able to start and stop the service.

I have created a COM Class called CTest with a methof called TestBeep(). I would like to access this object and call the method from the CServiceModule::Run() method.

Below is the CServiceModule::Run() Method.
The code will fail on both attempts to create the ITest* pTest using CoCreateInstance(). The error message are written to the event log
"Error: ITest failed"
"CoCreateInstance failed"

Any help is appreciated,
Thanks,
Chris

void CServiceModule::Run()<br />
{<br />
    _Module.dwThreadID = GetCurrentThreadId();<br />
<br />
    HRESULT hr = CoInitialize(NULL);<br />
//  If you are running on NT 4.0 or higher you can use the following call<br />
//  instead to make the EXE free threaded.<br />
//  This means that calls come in on a random RPC thread<br />
//  HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);<br />
<br />
    _ASSERTE(SUCCEEDED(hr));<br />
<br />
    // This provides a NULL DACL which will allow access to everyone.<br />
    CSecurityDescriptor sd;<br />
    sd.InitializeFromThreadToken();<br />
    hr = CoInitializeSecurity(sd, -1, NULL, NULL,<br />
        RPC_C_AUTHN_LEVEL_PKT, RPC_C_IMP_LEVEL_IMPERSONATE, NULL, EOAC_NONE, NULL);<br />
    _ASSERTE(SUCCEEDED(hr));<br />
<br />
    hr = _Module.RegisterClassObjects(CLSCTX_LOCAL_SERVER | CLSCTX_REMOTE_SERVER, REGCLS_MULTIPLEUSE);<br />
    _ASSERTE(SUCCEEDED(hr));<br />
<br />
    LogEvent(_T("Blue Service started"));<br />
    LogEvent(_T("Message 1"));<br />
    LogEvent(_T("Message 2"));<br />
<br />
    if (m_bService)<br />
        SetServiceStatus(SERVICE_RUNNING);<br />
<br />
    MSG msg;<br />
    while (GetMessage(&msg, 0, 0, 0))<br />
        DispatchMessage(&msg);<br />
<br />
    _Module.RevokeClassObjects();<br />
<br />
<br />
    // --------------------------------------------<br />
    // We will try to call the COM Object from here <br />
<br />
    char progID[] = "Blue.Test.1";<br />
<br />
    // Now make that object.<br />
    CLSID clsid;<br />
    wchar_t wide[80]; <br />
    mbstowcs(wide, progID, 80);<br />
    CLSIDFromProgID(wide, &clsid);<br />
<br />
    LogEvent(_T("Attempt to use ITest"));<br />
<br />
    ITest* pTest = NULL;<br />
    if(SUCCEEDED(CoCreateInstance(clsid, NULL, CLSCTX_ALL, IID_ITest, (void**)&pTest)))<br />
    {<br />
        pTest->TestBeep(); <br />
    }<br />
    else<br />
    { <br />
        LogEvent(_T("Error: ITest failed"));<br />
    } <br />
<br />
<br />
    // We will try this another way !! <br />
    // We have downloaded a ATL COM Server sample and it had <br />
    // A COM Method in in and it was not called from within the <br />
    // Service (as we are trying to do) it was called from a<br />
    // Windows Console Application using the following.  <br />
    // We would like to make this call into com from in the <br />
    // Service !! <br />
    <br />
    CComPtr<ITest> pObj;<br />
    hr = pObj.CoCreateInstance(OLESTR("Blue.Test.1"));<br />
    if( SUCCEEDED(hr) )<br />
    {<br />
        hr = pObj->TestBeep();<br />
        if( SUCCEEDED(hr) )<br />
        { <br />
            LogEvent(_T("Call to ITest was successful"));<br />
        }<br />
        else<br />
        { <br />
            LogEvent(_T("Error: ITest failed"));<br />
        } <br />
    }<br />
<br />
    if( FAILED(hr) )<br />
    { <br />
        LogEvent(_T("CoCreateInstance failed"));<br />
    }<br />
<br />
    CoUninitialize();<br />
}<br />
<br />

This is the implementation of the CTest Class and the TestBeep() method

// Test.h : Declaration of the CTest<br />
<br />
#ifndef __TEST_H_<br />
#define __TEST_H_<br />
<br />
#include "resource.h"       // main symbols<br />
<br />
/////////////////////////////////////////////////////////////////////////////<br />
// CTest<br />
class ATL_NO_VTABLE CTest : <br />
    public CComObjectRootEx<CComSingleThreadModel>,<br />
    public CComCoClass<CTest, &CLSID_Test>,<br />
    public IDispatchImpl<ITest, &IID_ITest, &LIBID_BLUELib><br />
{<br />
public:<br />
    CTest()<br />
    {<br />
    }<br />
<br />
DECLARE_REGISTRY_RESOURCEID(IDR_TEST)<br />
<br />
DECLARE_PROTECT_FINAL_CONSTRUCT()<br />
<br />
BEGIN_COM_MAP(CTest)<br />
    COM_INTERFACE_ENTRY(ITest)<br />
    COM_INTERFACE_ENTRY(IDispatch)<br />
END_COM_MAP()<br />
<br />
// ITest<br />
public:<br />
    STDMETHOD(TestBeep)();<br />
    STDMETHOD(GetCount)();<br />
    int nCount;<br />
};<br />
<br />
#endif //__TEST_H_<br />
<br />
<br />
<br />
// Test.cpp : Implementation of CTest<br />
#include "stdafx.h"<br />
#include "Blue.h"<br />
#include "Test.h"<br />
<br />
/////////////////////////////////////////////////////////////////////////////<br />
// CTest<br />
<br />
<br />
STDMETHODIMP CTest::GetCount()<br />
{<br />
    // TODO: Add your implementation code here<br />
<br />
    return S_OK;<br />
}<br />
<br />
STDMETHODIMP CTest::TestBeep()<br />
{<br />
    // TODO: Add your implementation code here<br />
    Beep(4000, 200); <br />
    Beep(1000, 50); <br />
    Beep(4000, 200); <br />
    Beep(1000, 50); <br />
    return S_OK;<br />
}<br />
<br />

Thanks,
Chris

LGPL query

Chintoo72322-Feb-06 5:51

Chintoo723

22-Feb-06 5:51

I want to take a bunch of unit test files from an LGPL opensource project, include them in my _closed_ project, modify them a bit and use it to test parts of my application. Can I do this?

thanks!

C^hris L^osinger22-Feb-06 7:45

C^hris L^osinger

22-Feb-06 7:45

Chintoo723 wrote:
Can I do this?

no[^].

The modified work must itself be a software library.

You must cause the whole of the work to be licensed at no charge to all third parties under the terms of this License.

Cleek | Image Toolkits | Thumbnail maker

Chintoo72322-Feb-06 15:21

Chintoo723

22-Feb-06 15:21

Chris Losinger wrote:
copy and distribute such modifications or work under the terms of Section 1 above,

What does distribute here mean? who wants my work? where should I publish it to call it distributed?

Chris Losinger wrote:
a) The modified work must itself be a software library.

As I said, it is only test modules which will be in a seperate .dsp project anways. Does this constitute a library in LGPL terms?

Chris Losinger wrote:
You must cause the whole of the work to be licensed at no charge to all third parties under the terms of this License.

Same query as the first one. How should I go about it to make sure I am hiding anything from any third parties that want to use it.

thanks!

C^hris L^osinger22-Feb-06 16:01

C^hris L^osinger

22-Feb-06 16:01

Chintoo723 wrote:
What does distribute here mean?

the same thing it means anywhere else: if you give it, sell it or let anyone else use it, you're distributing it.

Chintoo723 wrote:
How should I go about it to make sure I am hiding anything from any third parties that want to use it.

please, don't take this as legal advice... i'm not a lawyer

but, i think if anything you distribute (ie. let anyone else use outside your organization use) uses L/GPL code, you need to distribute all the code in that app/library. you can't break it up and put parts of it into closed-source apps or libraries.

the LGPL, as i understand it, lets you link LGPL libs into closed-source apps. but it doesn't let you use the code from those libs in closed-source apps.

Cleek | Image Toolkits | Thumbnail maker

Joe Woodbury22-Feb-06 8:26

Joe Woodbury

22-Feb-06 8:26

If used only for testing, I believe you can. The key is that you won't be shipping any binaries from code covered by the LGPL.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Sebastian Pipping22-Feb-06 15:40

Passing Arrays of structures from VB.NET to unmanaged C++

22-Feb-06 15:40

i'm really not sure at all but i think LGPL code in
combination with a closed source project is possible.

at least i got a probably promising pointer
for you: there's a whole chapter called
"The GPL, LGPL, and Mozilla Licenses"
in the free openbook from o'reilly:

>> Understanding Open Source and Free Software Licensing / Chapter 3

best regards, sebastian

-------------------------------------------
My website: http://www.hartwork.org

CPop22-Feb-06 5:45

CPop

22-Feb-06 5:45

I have been looking for an answer on this one, but found only references to structures. Basically I have a VB.NET structure containing an member array of onother structure that has to be passed to unmanaged C++. I have been able to pass the structure which has members of type structure, but as soon as I define a member array of that structure I get an error: "An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in mscorlib.dll
Additional information: The operation completed successfully."

This is how I am doing it:

VB.NET:

Public Structure SndStr2
<marshalas(unmanagedtype.i4)> Public memb1 As Integer
<marshalas(unmanagedtype.lpstr)> Public memb2 As String
<marshalas(unmanagedtype.i4)> Public memb3 As Integer
<marshalas(unmanagedtype.i4)> Public memb4 As Integer
End Structure

Public Structure SndStr1
<marshalas(unmanagedtype.i4)> Public memb1 As Integer
<marshalas(unmanagedtype.lpstr)> Public memb2 As String
<marshalas(unmanagedtype.i4)> Public memb3 As Integer
<marshalas(unmanagedtype.r8)> Public memb4 As Double
Public memb5() As SndStr2
End Structure

Declaration: Private Declare Function RcvFun Lib "...\RcvFun.dll" _
(ByRef SndVar As SndStr1) As String

Unmanaged C++:

struct RcvStr1 {
int memb1;
LPSTR memb2;
int memb3;
int memb4;
};

struct RcvStr2{
int memb1;
LPSTR memb2;
int memb3;
double memb4;
RcvStr1 *memb5;
};

LPSTR __declspec (dllexport) __stdcall RcvFun(RcvStr2 **RcvPtr)
{
RcvStr1 RcvVar1;

RcvVar1 = RcvPtr[0]->memb5[0];
return RcvVar1.memb2;

}

If there is anybody out there that did this before, please help! Confused | :confused:

-- modified at 12:05 Wednesday 22nd February, 2006

Listview controls

Waldermort22-Feb-06 5:23

Waldermort

22-Feb-06 5:23

I have created a Listview box which would display data in the Report mode. When filling in the header columns is it possible to set the width to correctly display the full text string?

Most of the examples I have found on the net either give the width a static value or a percentage of the total. I would prefer it if I could simply find the length in dialog units or pixels of the max string to be displayed and set the width according to that.

So far I have found no function which is able to find the length of a string in this manner? Is there a method to doing this or would it be easier to do something like (chars_in_string * static_size)?

Joe Woodbury22-Feb-06 5:41

Joe Woodbury

22-Feb-06 5:41

It's been a while since I did this, so if I don't get it exactly right, I apologize.

There is a member function of CListCtrl::GetStringWidth(), though I seem to recall it doesn't quite work as stated in the documentation. I seem to recall having to pad it slightly, but I may be mistaken.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Gavin Taylor22-Feb-06 6:07

Gavin Taylor

22-Feb-06 6:07

Following on from Joes comment above. Using the LVM_SETCOLUMNWIDTH[^] message, pass LVSCW_AUTOSIZE as the column width and the ListView will automaticaly resize the column to fit the longest string.

Gavin Taylor
w: http://www.gavspace.com

Sebastian Pipping22-Feb-06 10:32

22-Feb-06 10:32

funny we are working on the same thing at the same time.

i found a function calculating the width of a string
on MSDN. the column here contains numbers only so my code is

HDC hdc = GetDC( _hView );
SIZE size;
BOOL res = GetTextExtentPoint32( hdc, TEXT( "0" ), 1, &size );
ReleaseDC( _hView, hdc );
const int iWidth = res ? ( size.cx * _iDigits ) : 120;

this function can be still helpfull when you want
to size for the largest string of all, not just the visible
ones (which LVSCW_AUTOSIZE does).

also i found out you can size the last column
to take as much space as possible without adding the
horizontal scrollbar (unlike LVSCW_AUTOSIZE_USEHEADER):

RECT r;
GetClientRect( _hView, &r );
const int iWidth = ListView_GetColumnWidth( _hView, 0 );
ListView_SetColumnWidth( _hView, 1, r.right - r.left - iWidth );

best regards, sebastian

-------------------------------------------
My website: http://www.hartwork.org

Waldermort22-Feb-06 15:13

Waldermort

22-Feb-06 15:13

Thanks for the info. You say that LVSCW_AUTOSIZE only allows for the width of the visible items, I'm not sure I understand cleary.

1. The header items only?
2. Those which are in view due to scroll limits?

I will play around with it when I get home, thanks again.

Sebastian Pipping22-Feb-06 15:30

22-Feb-06 15:30

i'm not sure if it got you right but i guess
number 2 is what i meant

i'll try again with more details:
my column contains numbers from 1 to 4000.
when the current view is at the very top you can
only see numbers with one or tow digits.

applying LVSCW_AUTOSIZE now sets the
size to two digits not four since the big number
are out of view and ignored.

maybe i should mention my column header
has "#" as title so it is even shorter than
the numbers. i'm not sure what happens if the
header text is longer than all the row text.
i'm using the control in virtual/getdispinfo mode
maybe that's also playing in here!?

btw i had trouble with two-digit numbers shown
as "1..." so the current text width code is

const int iWidth = res ? ( int )( size.cx * ( _iDigits + 0.25f ) ) : 120;

i hope i put it clearly. i'm not a native speaker.

best regards, sebastian

-------------------------------------------
My website: http://www.hartwork.org