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Erkenntnisse zur DLL-Programmierung
Wenn man eine exportierte Klasse verwendet kann man diese nicht mithilfe von LoadLibrary und GetProcAdress nutzen. Klassen muss man über Load Time Linking verwenden, nicht über Run Time Linking. Eine Mischung aus Load Time Linking und Run Time Linking kann aber dennoch verwendet werden. Funktionen (in der DLL), die nicht Memberfunktionen von Klassen sind, lassen sich gleichzeitig über Run Time Linking ansprechen. Doch das ist dann ja sowioeso überflüssig, da alle Vorteile des Run Time Linking dahin sind.
Wenn die Funktion LoadLibrary Namen die vorhanden sind nicht findet, könnte das daran liegen, dass die Namen beim Compilieren und Linken verändert werden. Da wird zum Beispiel aus fnMyTREE dann ?fnMyTREE@@3HA. Zwei mögliche Lösungen: 1. Kann man per .DEF-Datei die korrekten (ursprünglichen) Namen vorschreiben, hier können sogar Aliase vergeben werden! 2. Kann man den veränderten Namen einfach in der GetProcAdress-Funktion verwenden: GetProcAddress(hinst,"?fnMyTREE@@3HA"); Das klappt!
Ich suche noch folgende Info´s:
Weiss irgendjemand von einem Script, das beschreibt, wie man DLL´s prinzipiell verwendet. Also Fragen zur Programmiertechnik wie z.B.:
Sollte ich eine DLL-interne Klasse in der Entry-Funktion allokieren?
Sollte man eine Kontroll-Klasse gänzlich der Aussenwelt verbergen?
Wer kennt sinnvolle Konstrukte oder mag mir mal seine Programmiermethoden offenbaren.
Wo findet man Codebeispiele zu diesem Thema?
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I've already posted similar question... but i still got this problem: i would like to rotate a char around it's center. I tried to use SetTextAlign, but it alligns the text only on top-center, or bottom-center, everything is not what i need... Who can help me with this question???
And how to get the width and the height of the char, that i try to write on my context device using GDI+??? where the similar function of GetTextExtent???
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Hi all,
Is there any way to check whether a stored procedure is present in the Database or not. Iam using SQL Server as the db and using ADO 4 programming using MS VC++ 6.0
Thanx in advance
Sujan
Note: I KNOW THAT WE CAN CHECK IT USING TRY-CATCH,IS THERE ANY OTHER WAY OTHER THAN THIS
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use the same query that the SQL generator to see if the stored procedure is there. It is a query of dbo.master.sysobjects.
Tim Smith
I'm going to patent thought. I have yet to see any prior art.
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Hi Tim,
Thanx a Lot i'll work with it. Sorry for replying late coz yesterday i not @ the office.
Thanx a Lot
Sujan
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Hi,
Could anyone get me the sample code for check mail and download the attachment to local path in Visual C++.
Thanks in Advance![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
Be simple and Be sample.
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from Where Buddy 
-----------------------------
"I Think It Will Help"
-----------------------------
Alok Gupta
visit me at http://www.thisisalok.tk
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Hi,
From where. If it is from Inet, you have use the CInternet session and its related classes, if it is from Outlook express then you have to use Outlook automation.
Sujan
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hi,
I need to check mail from Internet. How could i use CInternet session, is there any sample.
I need to create an MFC application to show all the mails from internet. I can provide pop address, userid and password. My application should download all the messages in that with full details (subject, from whom it comes, attached file etc...)
simply, I need to create MFC application similar to that of outlook but in my own format....
Thanks
Be simple and Be sample.
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Hi,
i had created an appln like this long time back. So i have to search for it.
But for now have a look @ the following link
http://visualcpp.net/index.php?qID=35
This will surely help you to start working with.
Best of luck
Sujan
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I have developed an app in VC++ to cutomize the IE.
I have a console based application which can be accessed thru this IE.The console app has many function keys supported for its own functionality.
My idea is to provide Function Key support from F1..F12 in the IE so that my console app can get those function keys when invoked from IE.
Pls help ..how to achieve this..
Is it possible to do...???
Thanks in advance
Ram
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Hi,
Have a look @ this article, sometimes it may help you
http://msdn.microsoft.com/library/default.asp?url=/workshop/browser/hosting/wbcustomization.asp
Sujan
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Hi!
I want to develop an applcation in VC6, which detect and then plot the graph of network traffic. This graph should be avaialble to user on a web browser.
I don't know where to start except somewhere I should be using winsock.
I am Intermediate level in Win32SDK and beginner for MFC.I hate java and want to prove that better things can be accomplished using VC than that Lazy Java.
Three Cheers for this forum and VC community
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yeah Buddy i am too the Vc Fan.
About your problem,you have to use iphelper api not
winsock.
there is good example of firewall by Sudhir Mangla
to get the network traffic.
about ploting the graph,from what ever i know,you
can follow this little logic or wait for other
Programmer to reply.
->if you familiar with any WebLanguage,just write
the data into the file and notify that webpage
about the data you have recieved from network to
disply it on WebBrowser
-----------------------------
"I Think It Will Help"
-----------------------------
Alok Gupta
visit me at http://www.thisisalok.tk
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if you familiar with any WebLanguage,
I know perl/cgi
just write the data into the file
This I can do
and notify that webpage about the data you have recieved from network to disply it on WebBrowser
How to do this?
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SiddharthAtw wrote:
and notify that webpage about the data you have recieved from network to disply it on WebBrowser
How to do this?
you can do this by reading the data file written by you network application at regular interval. easiest way i think.
-----------------------------
"I Think It Will Help"
-----------------------------
Alok Gupta
visit me at http://www.thisisalok.tk
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I am working in Crystal reports 10 in vc++ 6.0.
When i click the right mouse button an the empty report viewer it causes an exception.
I tried to catch the click and oncontextmenu events of the report viewer activex control but they only work if there is a report in the viewer.
How should i handle this exception.
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I am working with crystal reports 10 in vc++ 6.0 and need to create a new report. I am using the following piece of code.
#import "craxdrt.dll" no_namespace<br />
<br />
IApplicationPtr m_pApplication;<br />
IReportPtr m_pReport;
....
m_pApplication.CreateInstance("CrystalRuntime.Application");
....
Everyting goes fine till here. But as soon as i call the NewReport() method in the IApplicationPtr it throws a com exception.
m_pReport = m_pApplication->NewReport() throws a com exception.
Dont know whats going wrong.
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I'm assuming your CreateInstance has failed. What is the HResult returned from it.
I usually create a Crystal instance using
HRESULT hr = m_Application.CreateInstance(__uuidof(Application));
What exception is thrown? Have you added an exception handler to get more details of the exception?
try<br />
{<br />
m_pReport = m_pApplication->NewReport();<br />
}<br />
catch(_com_error& e)<br />
{<br />
TRACE("COM Error: %s %s %x\n", e.ErrorMessage(), (LPCTSTR)e.Description(), e.Error());<br />
}
Michael
CP Blog [^]
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Dear all,
I am using Microsoft VS 6 and when I first built my program's project with the app wizard I select the English Language for "what language would you like your resources in?".
My question is: after I have built the project, can I change the language DLL? The reason is becuase my software needs to work for several languages. In fact I am running a Chinese version of Windows and all the Chinese displays on using the English DDL, EXCEPT the list control. When Chinese is displayed in it, it comes out as rubbish. This is not the case with drop-down menus and text boxes? Anyone know why this might be?
I tried building a test project with just a List Control but used the Chinese DLL and it seems to be ok. So I am wondering if I can change the DLL my program uses now that I have built my program already with the English one.
Any help would much appreciated.
Graham.
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Hi all,
This is my first post in this A-real-time-code-site( The Code Project).
Before 2 months I purchased the Visual Studio.NET the acadimic version, and since that time I was trying to do some coding in Visual C++.net, VB.net and some smart phone applications. But the problem is that I don't know why so far I don't have the touch for that, I mean I have ideas but I can't deal with the .NET thing??!! putting in mind that Back in my electronic and telecomunnication school I was able to do many coding in the C++ ( Borland builder and others), But when I migrate to .NET, BANG, I don't have a clue.
Maybe it's like what MORPHUSE told NEO in ( The Matrix) " Knowing the path is not like wlaking on the path".
So please I need your advices and some tips and some really good books that you guys have worked with it.
Best Regards.
(C++) + simplicity = C++.net PRO.
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hi there,
i'm trying to make a class capable of playing wave files and returning play position and levels.
i'm using MCI functions and, for the most of it, it works ok.
for example, i get the play position using MCI_STATUS_POSITION:
DWORD CWave::GetPosition()
{
DWORD lnPos=0;
DWORD lnErr;
MCI_STATUS_PARMS loStatus;
loStatus.dwCallback=NULL;
loStatus.dwItem=MCI_STATUS_POSITION;
lnErr=mciSendCommand(m_nDeviceID, MCI_STATUS, MCI_STATUS_ITEM |MCI_STATUS_POSITION| MCI_WAIT,(DWORD) (LPMCI_STATUS_PARMS)&loStatus);
if(!lnErr)
{
lnPos=loStatus.dwReturn;
}
else
{
UINT lnErrL;
char * lsErr;
if(mciGetErrorString(lnErr,lsErr, lnErrL))
AfxMessageBox(lsErr,MB_ICONERROR);
else
AfxMessageBox("An unknown error occured",MB_ICONERROR);
}
return lnPos;
}
but i can't understand why MCI_WAVE_STATUS_LEVEL returns an error: "MMSYSTEM 322: All wave devices that can record files in this format are in use."
DWORD CWave::GetLevels()
{
DWORD lnLevels=0;
DWORD lnErr;
MCI_STATUS_PARMS loStatus;
loStatus.dwCallback=NULL;
loStatus.dwItem=MCI_WAVE_STATUS_LEVEL;
lnErr=mciSendCommand(m_nDeviceID, MCI_STATUS, MCI_STATUS_ITEM |MCI_WAVE_STATUS_LEVEL| MCI_WAIT,(DWORD) (LPMCI_STATUS_PARMS)&loStatus);
if(!lnErr)
{
lnLevels=loStatus.dwReturn;
}
else
{
DisplayErrorMsg(lnErr,"Error while getting levels");
}
return lnLevels;
}
....can anyone help???
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Hi,
I have to write a program that will talk to a device through USB. In the past I have built a program that is able to talk to devices through the RS232 COM ports. In this case Windows abstracts the Serial ports as just file handles. My question is, how exactly do I get at a USB device from a Visual C++ program? Are there Win32 API functions that will do it for me?
I have found lots of information about writing Windows USB drivers and they all say it is difficult because you need to have an understanding of the Windows kernel. However I don't think this information applies to me beacuse I just basically want to send bytes down to a USB device.
Thanks in advance!
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If you can, try to find a virtual serial port driver for your device which will map USB into something which will work with the WriteFile API. We used this approach for working with bluetooth USB dongles on our last project and it worked quite well.
If you can keep you head when all about you
Are losing theirs and blaming it on you;
If you can dream - and not make dreams your master;
If you can think - and not make thoughts your aim;
Yours is the Earth and everything that's in it.
Rudyard Kipling
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