Re: COM Framework - COM Discussion Boards

Roger Stoltz10-Apr-07 3:00

10-Apr-07 3:00

One of the constructors of _bstr_t takes a const char* as argument. Since CString has a type conversion operator LPCTSTR that returns a const char* you can do the following:

CString str = "The string";
_bstr_t bstrTest( str ); // When you declare your _bstr_t variable, or
bstrTest = _bstr_t( str ); // when assigning the variable

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Re: How to convert a CString to _bstr_t

Steve S10-Apr-07 5:16

Steve S

10-Apr-07 5:16

[fx: pedant mode on]

Roger Stoltz wrote:
Since CString has a type conversion operator LPCTSTR that returns a const char* you can do the following:

No it doesn't. It returns const TCHAR*, which in a UNICODE build won't be the same as const char*. However, _bstr_t has a constructor that accepts const wchar_t* as well as one for const char*, so it will work in either case.

[fx: pedant mode off]
Smile | :)

Steve S
Developer for hire

Re: How to convert a CString to _bstr_t

Roger Stoltz10-Apr-07 5:35

Roger Stoltz

10-Apr-07 5:35

Now you're just being picky Steve... but you're right of course. Big Grin | :-D

However, I think the OP got the picture and depending on the OP's level of expertise it may have been confusing to start talking about unicode.

"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown

Re: How to convert a CString to _bstr_t

Steve S10-Apr-07 21:55

Steve S

10-Apr-07 21:55

Of course I'm being picky. When you get to my age, it's one of the few pleasures left in life that doesn't cost money or end up causing some kind of muscular spasm... Dead | X|

I agree that it might have been confusing, which is one of the problems of CP. It's hard to know what level the OP is at (or in some cases, they think they're at), and that makes it difficult sometimes to give the 'right' answer, because they may end up worse off than before.

I did like the thread here[^] where someone else came in and finished explaining it while I was asleep Smile | :)

Steve S
Developer for hire

Empty DACL

San24689-Apr-07 23:44

San2468

9-Apr-07 23:44

How can I create an empty DACL?

Re: Empty DACL

Steve S10-Apr-07 5:22

Steve S

10-Apr-07 5:22

What do you want to do with it (apart from the obvious "put it into a security descriptor") ?

I'm sure there's stuff on MSDN about doing this, usually found by asking pointed questions about named pipes and such which are normally used by services, and the question is generally "why does it work when I run my server interactive, but not when it's a service"....

Steve S
Developer for hire

COM Framework

Gupta Suraj9-Apr-07 3:21

Gupta Suraj

9-Apr-07 3:21

Hi All,

1). Which is the COM service that creates stub and proxy for out-proc-server COM objects?
2). What makes up the COM frameworks?

~Suraj

Suraj Gupta

Re: COM Framework

sthotakura16-Apr-07 7:25

sthotakura

16-Apr-07 7:25

COM Framework

OLE32.dll [basic COM framework]
OLEAUT32.dll [ Automation and Marshalling ]
RPCRT4.dll [ Runtime to support Remote Procedure Calls ]

Cheers,
Suresh

Image viewer

MEmami6-Apr-07 21:17

MEmami

6-Apr-07 21:17

I need a free .ocx or .dll to view and zoom one of vector images (e.g. wmf images ).
Can you help me?
m_emami2002@yahoo.com

m_emami2002@yahoo.com

COM in C# for beginner

Stevo Z5-Apr-07 4:26

Stevo Z

5-Apr-07 4:26

Hi,

I need co create COM objects in C# and use them again in C#. I've good articles how to create COM but haven't found anything about how to use them in C# .

E_FAIL from COM Object

Hideaway765-Apr-07 4:16

Hideaway76

5-Apr-07 4:16

First post, so be gentle...

I didn't know where to post this, so I'll start here...

I have a COM DLL that is part of a 32bit executable application. The DLL relies on other files and DLLs to operate. I have a reference in VS.NET 2K5 to the DLL and when working locally, the DLL does exactly as it's supposed to.

Now here's the problem. When I upload my site, the DLL breaks and returns "Error HRESULT E_FAIL has been returned from a call to a COM component".

This could mean one of two things:
1. The COM DLL encountered an error.
2. The COM DLL is nowhere to be found.

I installed the application on our server. I registered the COM DLL. And I can locate the DLL using System.IO.File.Exists. But it's still failing.

So I have a two part question:
1. Can I load the DLL dynamically using Reflection and have the same access to its members?
2. Is there a magic way to register the DLL in the GAC and not break the linkage to its other resources?

I've never worked with COM objects before so my experience is somewhat limited.

Any help on this is GREATLY appreciated!!

-Daniel

toolbar button_click event

aamn15-Apr-07 2:27

aamn1

5-Apr-07 2:27

Hi,
i have an toolbar button on IE, and i just want to show an html popup with js effects on click event and again hide that popup on mousemove event,
i try to access js file from vb6.0 but not getting the desired results...
please try to give any link or suggesitons over this(call html/js attach to command button on ie)

thanks in advance.
amolk

amolk

DCOM (Transferring of binary files.)

Don Box2-Apr-07 23:32

Don Box

2-Apr-07 23:32

I want to send and receive the binary data across systems. The problem I'm facing is, when a binary file is read and it is sent, the binary data will be sent upto the first encountering NULL character. So I'm wondering, how can I send.
Plzzzzz, help me in this issue.
Suggestions would be greatly appreciated.

Come online at:-
jubinc@skype

Re: DCOM (Transferring of binary files.)

lafleon3-Apr-07 12:39

lafleon

3-Apr-07 12:39

Hello,

Just try:
*.idl: HRESULT FunName([in,out] SAFEARRAY(BYTE)* pbtBufData);
*.h : STDMETHOD(FunName)(SAFEARRAY** pbtBufData);
*.c : STDMETHODIMP CClassName::FunName(SAFEARRAY** pbtBufData){...}

Regards,

Re: DCOM (Transferring of binary files.)

Don Box3-Apr-07 20:25

Don Box

3-Apr-07 20:25

ThanX lafleon very much!
I'll try with this.

Come online at:-
jubinc@skype

Monitor Activex/COM object Instantiation

__Azzy2-Apr-07 8:49

__Azzy

2-Apr-07 8:49

Hi,

I was wondering is it possible to monitor all the Active/COM objects as they are being instantiated by programs. I think it should be possible by hooking into the API that is used to get the interfaces to them. I have been trying to figure out which components are missing or not registered in the system but it is just too much pain trying to guess. I have searched on the net but have not found anything useful on the topic.

Thanks

VT_DISPATCH variant

asdtry1-Apr-07 23:57

asdtry

1-Apr-07 23:57

Hi I have a object.And i want to convert it into VT_DISPATCH variant.How can i do this.

Re: VT_DISPATCH variant

Vi24-Apr-07 19:04

Vi2

4-Apr-07 19:04

VARIANT v;
V_VT(&v) = VT_DISPATCH;
obj->QueryInterface(IID_IDispatch, (void**)&V_DISPATCH(&v));
...
VariantClear(&v);

With best wishes,
Vita

Where should I call CoUninitialize

Hariom Tiwari1-Apr-07 20:59

Hariom Tiwari

1-Apr-07 20:59

Hi,
I have declared a smart pointer of COM interface globally.
When I call CoUninitialize in ExitInstance it throws an exception.
Because it is trying to release interface pointer twice.
How can I overcome this problem?
I have to declare interface pointer globally.

Hari om Tiwari

Re: Where should I call CoUninitialize

prasad_som1-Apr-07 21:34

prasad_som

1-Apr-07 21:34

You are not supposed to call any COM API after calling CoUninitialize.
By declaring a com smart pointer globally, you are making call to IYourInterface-->Release() function.

Prasad
Notifier using ATL | Operator new[],delete[][^]

How to create a service

simonr62831-Mar-07 21:05

simonr628

31-Mar-07 21:05

Hello,

I have recently come across IServiceProvider::QueryService...
and although can use this function, do not know how the
services are created and what creates the SID_ constants.
I have used COM and come across CLSID_, IID_, but not SID_
Would you know the procedure for creating a service, using c++.

I use COM, visual c++ 6.0, c++ .NET 7.1.

Thankyou

Full idlist for a folder [modified]

CodeBerserker30-Mar-07 12:13

CodeBerserker

30-Mar-07 12:13

Hi all,

In my code I have an IShellFolder object and a relative pidl to one of its subfolders, and I need to get the full pidl to the subfolder. If I use subfolder->GetDisplayNameOf() with SHGNO_FORPARSING and then calls desktopFolder->ParseDisplayName() with the display name I get the full pidl for pure file system and pure virtual objects. But for virtual objects with file system storage (for example “My Music”) it does not work, I get the pidl to the storage (that is “My Computer/Drive c:/Documents and Settinings/…”) and that is not what I want, I want the pidl to the virtual folder, that is “My Documents/My Music”. So, does anyone have any ideas how to get the full pidl to the virtual part of a folder that has both a virtual and a file system folder given its parent and a relative pidl?

-- modified at 7:44 Sunday 1st April, 2007

Re: Full idlist for a folder

CodeBerserker5-Apr-07 10:15

CodeBerserker

5-Apr-07 10:15

Please

help me with this one, I cannot get around it.

issue reading records from SQL CE 2005

vvr198329-Mar-07 23:18

vvr1983

29-Mar-07 23:18

I have written a class for operating the SQLCE database with OLE DB, it work perfect on INSERT ,UPTDATE and so on, but when I use 'select' statement to get values from database it doesn’t return values properly even though the GetNextRows method succeeds.

HRESULT hr = NOERROR;
m_pIRowset = NULL;
m_prghRows = &m_rghRows[0];
hr = pICmdText->SetCommandText(DBGUID_SQL, pwszQuery);
if(!FAILED(hr))
{
hr = pICmdText->Execute(NULL, IID_IRowset, NULL, NULL, (IUnknown **)&m_pIRowset);
if (FAILED(hr)){
AfxMessageBox(_T("failed"));
m_pIRowset = NULL;
}
// Get IColumnsInfo interface
hr = m_pIRowset->QueryInterface(IID_IColumnsInfo, (void**)&m_pIColumnsInfo);
if(FAILED(hr)){
AfxMessageBox(_T("failed"));
}
// Get the column metadata m_ulNumCols//m_pDBColumnInfo
hr = m_pIColumnsInfo->GetColumnInfo(&m_ulNumCols, &m_pDBColumnInfo,&m_pStringsBuffer);
if(FAILED(hr) || 0 == m_ulNumCols){
AfxMessageBox(_T("failed"));
}
// Create a DBBINDING array.
m_dwBindingSize = m_ulNumCols;
m_prgBinding = (DBBINDING*)CoTaskMemAlloc(sizeof(DBBINDING)*m_dwBindingSize);
if (NULL == m_prgBinding){
hr = E_OUTOFMEMORY;
AfxMessageBox(_T("Memory allocation failure"));
}
// Set initial offset for binding position
m_dwOffset = 0;
// Prepare structures to create the accessor
UINT lCount;
ULONG dwOrdinal;
for (lCount = 0; lCount< m_ulNumCols; lCount++)
{
dwOrdinal = m_pDBColumnInfo[lCount].iOrdinal;
m_prgBinding[lCount].iOrdinal = dwOrdinal;
m_prgBinding[lCount].dwPart = DBPART_VALUE | DBPART_STATUS | DBPART_LENGTH;
m_prgBinding[lCount].obLength = m_dwOffset;
m_prgBinding[lCount].obStatus = m_prgBinding[lCount].obLength + sizeof(ULONG);
m_prgBinding[lCount].obValue = m_prgBinding[lCount].obStatus + sizeof(DBSTATUS);
m_prgBinding[lCount].wType = m_pDBColumnInfo[lCount].wType;
m_prgBinding[lCount].pTypeInfo = NULL;
m_prgBinding[lCount].pObject = NULL;
m_prgBinding[lCount].pBindExt = NULL;
m_prgBinding[lCount].dwMemOwner = DBMEMOWNER_CLIENTOWNED;
m_prgBinding[lCount].dwFlags = 0;
m_prgBinding[lCount].bPrecision = m_pDBColumnInfo[lCount].bPrecision;
m_prgBinding[lCount].bScale = m_pDBColumnInfo[lCount].bScale;
switch(m_prgBinding[lCount].wType){
case DBTYPE_WSTR:
m_prgBinding[lCount].cbMaxLen = sizeof(WCHAR)*(m_pDBColumnInfo[lCount].ulColumnSize + 1); // Extra buffer for null terminator
break;
default:
m_prgBinding[lCount].cbMaxLen = m_pDBColumnInfo[lCount].ulColumnSize;
break;
}
// Calculate the offset, and properly align it
m_dwOffset = m_prgBinding[lCount].obValue + m_prgBinding[lCount].cbMaxLen;
m_dwOffset = ROUND_UP(m_dwOffset, 8);
}
// Get IAccessor interface
hr = m_pIRowset->QueryInterface(IID_IAccessor, (void**)&m_pIAccessor);
if(FAILED(hr))
{
AfxMessageBox(_T("failed"));
}
// Create the accessor
//
hr = m_pIAccessor->CreateAccessor(DBACCESSOR_ROWDATA, m_dwBindingSize,
m_prgBinding, 0, &m_hAccessor,NULL);
if(FAILED(hr))
{
AfxMessageBox(_T("failed"));
}
// Allocate data buffer.
//
m_pData = (BYTE*)CoTaskMemAlloc(m_dwOffset);
if (NULL == m_pData)
{
hr = E_OUTOFMEMORY;
CString errors;
errors.Format(_T("%d"),m_pDBColumnInfo[2].ulColumnSize);
MessageBox(NULL,errors,NULL,MB_OK);
AfxMessageBox(_T("failed"));
}
// Retrive a row
//
hr = m_pIRowset->GetNextRows(DB_NULL_HCHAPTER, 0, 1, &m_cRowsObtained,&m_prghRows);
if (SUCCEEDED(hr) && hr != DB_S_ENDOFROWSET)
{
// Set data buffer to zero
//
memset(m_pData, 0, m_dwOffset);

// Fetch actual data
hr = m_pIRowset->GetData(m_prghRows[0], m_hAccessor, m_pData);

if (FAILED(hr))
{
m_pIRowset->ReleaseRows(1, m_prghRows, NULL, NULL, NULL);
AfxMessageBox(_T("failed"));
}
}
if (hr == DB_S_ENDOFROWSET)
{
m_bIsEOF = TRUE;
}
}

venkat

Excel Interop Issues

Steven M Hunt29-Mar-07 10:25

Steven M Hunt

29-Mar-07 10:25

I'm working on an excel application with data validation in it. The boss insists we use form controls such as checkbox or radio button. Is there any way to integrate these into an excel spreadsheet through COM Interop? If so, please provide an example or post a link. Also, we need to read the excel spreadsheet back through COM, so the controls need to be accessible later.

-- Steven Hunt

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