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Hi viliam,
Perhaps the following URL should throw some light on your doubts:
http://www.csharphelp.com/archives/archive43.html
(Though the article is again in C#, the concept should in fact be shared. Is'nt it?)
Deepak Kumar Vasudevan
http://deepak.portland.co.uk/
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to open a connection...
hr = pConn->Open(L"Provider=sqloledb; Data Source=127.0.0.1; Initial Catalog=realtime", L"sa", L"sa", NULL);
however, this time, i need to concatenate my connection string:
this->m_pszConn = new char[nLenConn+1];
strcpy(this->m_pszConn, this->m_pszProvider);
strcat(this->m_pszConn, this->m_pszDataSource);
strcat(this->m_pszConn, this->m_pszInitialCat);
how can I convert m_pszConn to Unicode? This is what the "L" macro does right? from char* to Unicode? And is "L" a macro by the way?
I can't do this:
pConn->Open( L m_pszConn, ....);
Thanks.
norm
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L requires a constant, i.e. a string in quotes. Instead if you have a char *, you should change this member to a _bstr_t. This wrapper will allow it's internal value to be set by either a narrow or wide string, it keeps two internally, and only builds the one it does not have when the operator asks for it. So you can pass it as a BSTR, or as a char *, and being a wrapper, it even cleans up after itself.
Christian
No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
Hey, at least Logo had, at it's inception, a mechanical turtle. VB has always lacked even that... - Shog9 04-09-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002
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I'm trying to use an activex component in a container. I created it using the dialog box wizard and created a member variable for the control. This all works fine, but I need to initialise a property that the control uses at run-time, i.e. while creating the control.
How do I access (and use) this persistent data stream?
I can initialise properties fine via the dialog box editor, but I want to be able to change one property value at initialisation of the control. Note: I know how to set the properties after the control has been initialised, but this essential peice of data I want to use only gets read once at initialisation/creation of the control, so after that event it's too late 
I'm looking at the msdn info for CreateControl, and I imagine I need to pass in some info in the "CFile* pPersist" parameter, but I can't find any reference to the structure of this.
Debbie
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You'll want to look at implementing IPersistStream or IPersistStreamInit (the latter allows you to initialize a persistent stream when one does not already exist). The CFile* pPersist is a stream that actually gets loaded with IPersistStream::Load(). If you look at MSDN for documentation about this interface, I'm sure you'll find everything start to fall into place.
As a side note, this is a basic component of ActiveX controls and how containers (like Word, Excel, the ActiveX Control Test Container, etc.) work. When those documents are saved, the application creates an IStream which is passes as a pointer to all its child controls' IPersistStream::Save methods. The child controls (OLE at a minimum, but can be ActiveX) save their information to this IStream* while the application calls IPersist::GetClassID() to associate the control's CLSID with that particular section of the finished IStream. This is all part of the COM persistence model. The container application actually implements IPersistStorage itself, so that it can load a file and create an IStream from it, or vice-versa to save it.
"Well, I wouldn't say I've been missing it, Bob." - Peter Gibbons
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I made a dialog for my project using VC's graphical dialog editor. I'd like to use this exact same dialog in several other projects, but I'm not sure how to do it short of cutting and pasting from the .rc and resource.h files.
My code for the dialog is in a its own file, in a common directory for all the projects, so my only issue is in sharing the resources for it.
Any suggestions?
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Solution 1 : build a .rc out of this dialog and put all #define symbols from the resource.h in it. Then, in all other projects, you just have to do a #include .rc in the .rc file. Warning : IDs conflict may arise, you are going to need an ID lookup solver/sorter.
Solution 2 : build a separate DLL and put that dialog into it.
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It's very simple task to do!
In class view right-click on the CDialog-derived class and select 'Add to Gallery'. Thats it.
Next time, when you want to add this dialog to other project, go to menu 'Project\Add to project\Components and Controls...'
you'll find there your dialog
or you may create a MFC-extention DLL and place this dialog there. then you'll use this dll in all your projects.
Dmitry Timin
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The best solution is to bring the dialog in a dll. Than you haven´t to compile it in any of your projects!!!
Try this @ home. (B&B)
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Hi,
Please do give me an idea, a brief idea, in designing and writing
a Code Generator in VC++, similar to Visual Studio's ClassWizard and
Appwizard.
I want to incorporate this in a different software product.
Regards,
Anind
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Firstly,you should prepared some code since computer not know what are the code you want. Then give user a UI window to select options. All that just like appwizard, use it may be better.
I am seeking...
For what?
Why did you ask me for what? I don't know!
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i wrote a dll in vc++,which iam calling from vb app. iam creating a window when i call the function called createwindowfunction from vb.iam closing the window and i again create the window by calling that function from vb app.when i close the window,the global variables are not cleared from memory.so when i call createwindow again the values are retained.how should i close the instance and to clear the variables.i think there is some way to close the instance.
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Global variables retain their values until you unload library. Consequently, you must use LoadLibrary and FreeLibrary to getting results, which you are expecting. AFAIK it's not easy to get function's address from DLL at runtime in VB. Then I would offer to write special function that cleans all global variables and call it explicitly... or clean your variables at window destruction
I beg pardon, if I misunderstood your question
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You are right Mr.Roman.
i declared global variables like int char etc before the main function.if iam using freelibrary in the wm_close,then the vb application also gets closed.so i tried to use the globalfree function for int,char etc.but also the variables in memory are not released.
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Hello, folks,
I got trouble using one of the DirectShow sample filters, i.e, Ball filter.
I got a link error. If I compiled and linked the code sample, the filter would generate something like ball.ax.
Could anyone tell me how to use this ball.ax ? I have included required *.h and ball.lib but I still got a linking error ? The linking error is as follows:
BallAppDlg.obj : error LNK2001: unresolved external symbol "public: __thiscall CBouncingBall::CBouncingBall(struct IUnknown *,long *)" (??0CBouncingBall@@QAE@PAUIUnknown@@PAJ@Z)
../Release/BallApp.exe : fatal error LNK1120: 1 unresolved externals
Anybody help me ? Any response would be greatly appreciated ! Thanks !
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Before you get to compile and link a DirectX sample, you need to go to MSDEV Tools \ Options \ Directories tab, and move the DirectX include/source/lib directories to the top.
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>>DirectX include/source/lib directories to the top.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Hello, thanks for you reply first.
On my system I have installed Platform SDK and DirectX 8.0 SDK. It seems the DirectX 8.0 SDK has been integrated with Platform SDK. So, I can NOT find the
DirectX include/source/lib directory as you menthioned.
Could you explain a little more detail ? Or what should I install on my system ? Thanks for your help again.
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manio wrote:
On my system I have installed Platform SDK and DirectX 8.0 SDK. It seems the DirectX 8.0 SDK has been integrated with Platform SDK
Depends if you have a recent platform SDK.
I would suggest to add the <directXsdk\lib> directory in MSDEV \ Tools \ Options \ Directories \ Library.
May be the problem is somewhere else. Lookup the public MS DirectShow newsgroup (or google, of course). I remember I have seen this kind of question again and again in the past, and from what I remember it was just a matter of directories.
I would suggest
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I made a lil' app on a NT4.0 system. It works fine. But when I run my prog on a windows '98 it just didn't work. When I recompiled the prog on the '98 it worked fine. When I run it I get a c++ exception. Now, I don't think that's the big problem. The problem is that in a method like this:
void HTML::HTML_FileHeader(char* filename,char* pagehead,char* tableheader) {
fileout.open(filename,ios::trunc);
CString mesaj;
char text[100];
fileout<< "<html>\n"
"<head>\n"
"</head>\n"
"<body>\n"
"<h2 align=center>";
fileout<< pagehead;
mesaj.Format(" %d, data de %d",time.GetHour(),time.GetDay());
strcpy(text,(LPCTSTR)mesaj);
fileout<< text;
fileout<< "</h2><table border=1 align=center>\n"
"<tr>\n"
"<th>ORAS</th>\n";
fileout<< tableheader<<"</tr>\n";
}
doesn't work.
fileout.open(filename,ios::trunc); doesn't work. He doesn't like the (char *)filename. If i replace filename with the actual file that it has to open it works fine. This happens in every method of the class. He doesn't like getting that. If I debug it the content of filename is correct. This is very odd (to me).
When I create a new win32 console app and I open a file that way in the main function it works fine. !!!!
I also open databases from methods opendatabase(databasename). This also doesn't work until I replace the databasename with the actual db name "databasename".
What am I doing wrong ?????? Somebody knows anything about this problem ?
P.S. I get the c++ exception because I'm trying to open a db and since he doesn't like the arguments like that (see below) it doesn't work
DBDatabase = DBEngine.OpenDatabase ( text );
DBRecordset = Database.OpenRecordset((LPCTSTR)openstring,dbOpenDynaset,dbDenyWrite);
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This is a problem of the filename. You should use the complete path. Maybe you should check that the file exist before you open it. (If not a messagbeox, for the alpha-release)
Remember: exception handling is best practice, get the exception message in a box.
If recompiling helps it maybe also that different version are installed on different machines. (header, code, libs, dll)
You godda puzzle some bits.
Try this @ home. (B&B)
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I can't use the complete path. This is not a solution because I have more than one file to be opened. And I checked for the existance of the filename. And it doesn't work neither when I try to open a database the same way I do the file. And EXCEPTION HANDLING -- I got the following answer:win32 exception. That helps alot 
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I had THIS problem also, it resolved that file couldn´t be found in the release-mode, because of the working directory and relative path. Not working with the complete path isn´t good style and you have your results.
And more than one file open can also be an architectual problem. Try to handle one file or db after the other. Or merge the file / dbs.
You get an exception, because the programmer of the code you want to use had implemented it!!! Look for it!!!
Try this @ home. (B&B)
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BlackRider wrote:
the following answer:win32 except
Try to show the value of GetLastError()
My latest article:
SQL Server DO's and DONT's[^]
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how can i determine whether the current user (whoever launch my exe) is "Administrator" or member of "Administrators"??
two scenario:
(a) local user
(b) active directory user
Thanks
norm
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static inline BOOL IsAdmin(void) {
HANDLE hToken;
DWORD dwStatus;
DWORD dwAccessMask;
DWORD dwAccessDesired;
DWORD dwACLSize;
DWORD dwStructureSize = sizeof(PRIVILEGE_SET);
PACL pACL = NULL;
PSID psidAdmin = NULL;
BOOL bReturn = FALSE;
PRIVILEGE_SET ps;
GENERIC_MAPPING GenericMapping;
PSECURITY_DESCRIPTOR psdAdmin = NULL;
SID_IDENTIFIER_AUTHORITY SystemSidAuthority = SECURITY_NT_AUTHORITY;
__try {
ImpersonateSelf(SecurityImpersonation);
if (!OpenThreadToken(GetCurrentThread(), TOKEN_QUERY, FALSE,
&hToken)) {
if (GetLastError() != ERROR_NO_TOKEN)
__leave;
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY,
&hToken))
__leave;
}
if (!AllocateAndInitializeSid(&SystemSidAuthority, 2,
SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS,
0, 0, 0, 0, 0, 0, &psidAdmin))
__leave;
psdAdmin = LocalAlloc(LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH);
if (psdAdmin == NULL)
__leave;
if (!InitializeSecurityDescriptor(psdAdmin,
SECURITY_DESCRIPTOR_REVISION))
__leave;
dwACLSize = sizeof(ACL) + sizeof(ACCESS_ALLOWED_ACE) +
GetLengthSid(psidAdmin) - sizeof(DWORD);
pACL = (PACL)LocalAlloc(LPTR, dwACLSize);
if (pACL == NULL)
__leave;
if (!InitializeAcl(pACL, dwACLSize, ACL_REVISION2))
__leave;
dwAccessMask= ACCESS_READ | ACCESS_WRITE;
if (!AddAccessAllowedAce(pACL, ACL_REVISION2,
dwAccessMask, psidAdmin))
__leave;
if (!SetSecurityDescriptorDacl(psdAdmin, TRUE, pACL, FALSE))
__leave;
SetSecurityDescriptorGroup(psdAdmin, psidAdmin, FALSE);
SetSecurityDescriptorOwner(psdAdmin, psidAdmin, FALSE);
if (!IsValidSecurityDescriptor(psdAdmin))
__leave;
dwAccessDesired = ACCESS_READ;
GenericMapping.GenericRead = ACCESS_READ;
GenericMapping.GenericWrite = ACCESS_WRITE;
GenericMapping.GenericExecute = 0;
GenericMapping.GenericAll = ACCESS_READ | ACCESS_WRITE;
if (!AccessCheck(psdAdmin, hToken, dwAccessDesired,
&GenericMapping, &ps, &dwStructureSize, &dwStatus,
&bReturn)) {
printf("AccessCheck() failed with error %lu\n", GetLastError());
__leave;
}
RevertToSelf();
} __finally {
if (pACL) LocalFree(pACL);
if (psdAdmin) LocalFree(psdAdmin);
if (psidAdmin) FreeSid(psidAdmin);
}
return bReturn;
}
This is what I use to check for domain Admins. I found it on MSDN somewhere I don't recall and adapted for my specific use. You can use it as a starting point.
My latest article:
SQL Server DO's and DONT's[^]
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