Re: Virtual Inheritance - C / C++ / MFC Discussion Boards

monsieur_jj10-Dec-07 21:40

10-Dec-07 21:40

Hi all,

I encountered something that affects the embedded attachments in converting a MAPI to MIME message, I need my mimeheader to be multipart/related for the embedded attachments and multipart/mixed for the body and the regular attachments. At the ATL mime only multipart/mixed is available, Can anyone help me constructing a new boundary correctly and making the multipart/related header too.

thanks,
Jj

Problem in opening the HTML file.

sanjeeva K Kanakam10-Dec-07 21:30

sanjeeva K Kanakam

10-Dec-07 21:30

Hello all, I am developing one application, in that have created one report file with HTML tags. I am opening that in my application it self. If the report file is big then my application is displaying a message "Cannot create unique tag name,giving up". I did not understand this message. Can you please tell me how can i avoid this ?

Re: Problem in opening the HTML file.

Christian Graus10-Dec-07 22:19

Christian Graus

10-Dec-07 22:19

How are you opening it ? What is throwing the error ?

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

Re: Problem in opening the HTML file.

Hamid_RT11-Dec-07 0:02

Hamid_RT

11-Dec-07 0:02

How did you try it and what was your code?

Re: Problem in opening the HTML file.

sanjeeva K Kanakam11-Dec-07 20:09

sanjeeva K Kanakam

11-Dec-07 20:09

I have created a file which contains tables, text and a tree manner view also with HTML tags. No problem in opening this file if the file is small. If the file is big then my application is displaying a message "Cannot create unique tag name, giving up",

Re: Problem in opening the HTML file.

Hamid_RT14-Dec-07 18:39

Hamid_RT

14-Dec-07 18:39

How did you read it?

Virtual Inheritance

Nik123410-Dec-07 21:25

Nik1234

10-Dec-07 21:25

Hi everyone,

I came to the point where I would like to use virtual inheritance (don't ask why Smile | :)

). Although I have found several info on the web and I am pretty sure how I am going to use it, I have one problem left:

INCLUDE FILES.

All articles describe how to use virtual inheritance, but always in one file, something rarely useful in large projects. Everything I tried with #include files doesn't work. Here is my example:

-----------------------------------------------------------------------
// file Base.h
#ifndef BASE_H
#define BASE_H

class Base{

public:
Base();
virtual ~Base();
};

#include "Derive1.h"
#include "Derive2.h"

#endif

-----------------------------------------------------------------------
// file "Base.cpp"
#include "Base.h"

Base::Base(){}
Base::~Base(){}
-----------------------------------------------------------------------

// file Derive1.h
#ifndef DERIVE1_H
#define DERIVE1_H

#include "Base.h"

class Derive1 : public virtual Base{

public:
Derive1();
virtual ~Derive1();
};

#include "Join.h"

#endif
-----------------------------------------------------------------------
// file Derive1.cpp
#include "Derive1.h"

Derive1::Derive1(){}
Derive1::~Derive1(){}
-----------------------------------------------------------------------

// file Derive2.h
#ifndef DERIVE2_H
#define DERIVE2_H

#include "Base.h"

class Derive2 : public virtual Base{

public:
Derive2();
virtual ~Derive2();
};

#include "Join.h"

#endif

-----------------------------------------------------------------------
// file Derive2.cpp
#include "Derive2.h"

Derive2::Derive2(){}
Derive2::~Derive2(){}
-----------------------------------------------------------------------
// file Join.h
#ifndef JOIN_H
#define JOIN_H

#include "Derive1.h"
#include "Derive2.h"

class Join : public Derive1, public Derive2{

public:
Join();
virtual ~Join();
};

#endif
-----------------------------------------------------------------------
// file Join.cpp
#include "Join.h"

Join::Join(){}
Join::~Join(){}
-----------------------------------------------------------------------
// file main.cpp
#include "Base.h"

int main(){

Join test;
return 0;
}
-----------------------------------------------------------------------

This will not compile, probably because both Derive1.h and Derive2.h include Join.h. However, any combination I've tried didn't solve me the problem and the program still wont compile.

Any clues anyone?

Thanx,
Nik

Re: Virtual Inheritance

Cedric Moonen10-Dec-07 21:33

Cedric Moonen

10-Dec-07 21:33

First, please use the pre or code tags to format your code properly.

Now, for your question: you can remove all the includes that you put at the end of your files, you don't need them and they cause the problem. Include simply means that the compiler will replace the directive by 'pasting' the code from the included file. So, guess what happens if file1 includes file2 which in turn include file1 ? Yes, that's infinite recursion Poke tongue | ;-P

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Virtual Inheritance

Nik123411-Dec-07 1:07

Nik1234

11-Dec-07 1:07

Firstly, thanx for your answer.

True, but infinite recursion is avoided by the #ifndef directives. The reason I am putting them there is that I only want to include my Base class in the main program. If I remove them, then I have to include all the different files (Derive1, Derive2, Join).

In all other cases, this pattern works fine. But because in this case there is a "diamond" structure of inheritance (that's why I use virtual inheritance), this causes the problem here.

Is there any way to keep this pattern (I only want to include my "Base.h" file in "main.cpp") and still complile somehow?

Re: Virtual Inheritance

Cedric Moonen11-Dec-07 1:33

Cedric Moonen

11-Dec-07 1:33

What's the exact error message ? It's really difficult to guess what the problem might be just by looking at your source code (unformatted).

Nik1234 wrote:
The reason I am putting them there is that I only want to include my Base class in the main program. If I remove them, then I have to include all the different files (Derive1, Derive2, Join).

Wrong: you just need to include Join.h because it already includes Derive1 and Derive2 and both of them include Base.h. And in general it is bad design to include the header files of the derived classes in the header of your base class (your base class should't be aware of its derived classes).

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Virtual Inheritance

Nik123411-Dec-07 1:55

Nik1234

11-Dec-07 1:55

Actually you are right, it seems a bad design. True, in this case I would only need to include the Join class, but if I had 100 Join classes, I would need to include all of those...

So, I am changing my design by removing the include files at the end of the base class and creating another include file which will include my derived classes(the 100 Join classes Smile | :)

). By this way I will still include only one file and I will avoid the other conflicts Poke tongue | ;-P

For your reference, the error I was getting was:

Derive1 class undefined
Derive2 class undefined

in the Join.h file.

Thanx a lot for your help!

[Done, may not good enough] GDI+ How to set a region without its constructor?

followait10-Dec-07 20:43

followait

10-Dec-07 20:43

How to set a region without its constructor?
With "new", it is less efficient.

OnMouseMove()
{
    Region Rgn;
    m_pic.GetRegion(&Rgn);    //Is it possible to be done efficiently?
                              //If can't, I'll use GraphicsPath instead
                              //of Region as a parameter.
}

Take the advange of MakeEmpty and Union, it can be done. Not sure if there is a more efficient way.

Re: [Done, may not good enough] GDI+ How to set a region without its constructor?

Mark Salsbery11-Dec-07 6:15

Mark Salsbery

11-Dec-07 6:15

followait wrote:
Take the advange of MakeEmpty and Union, it can be done.

There's not any other options if you don't want to return
a Region created with new.

Moving the Rgn variable out of the OnMouseMove() function will
help by avoiding the constructor/destructor calls.

Mark

Mark Salsbery
Microsoft MVP - Visual C++

Java | [Coffee]

Deny Taking Ownership

narayanagvs10-Dec-07 19:52

narayanagvs

10-Dec-07 19:52

Hi,

My System is in a Network Domain.
I need to protect a File/Folder from getting copied by other users.I worked on Access
Control Entries and provided permissions to a folder so that it can be accessed programmatically only. If I Click on that folder it says Access Denied.
I have given List Folder contents permission and Traverse and Read Permissions and allowing access to only my user name.

Unfortunately I found that by right clicking on the folder->Security Tab-> Advanced-->owner tab

the user can Replace the owner and and can have full control to folder.
Is there any possibility for me to disable that option?
or else atleast can we remove the security tab option from properties for that specific folder.

I need an approach.

Any thoughts would be greatly appreciated.

Thanks
Satya

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

Problem using sleep function. [modified]

nitin310-Dec-07 19:21

nitin3

10-Dec-07 19:21

//iam tring to show progressdialog on click ok button on Main dialog and update the WindowCaption in an interval of 1 sec. my problem described below..

HWND hWnd ;

void  ProgressFunc(HWND hwnd , char* progress )
{	
   SetWindowText( hWnd , progress ) ;

  <font color="green">//Update progress text by changing window title  </font>
}


DWORD MyProgressDlgThread(LPVOID Nothing )
{
    DialogBox(hInst,MAKEINTRESOURCE(IDD_PROGDLG1), ... ) ;
    <font color="green">//i set the value of global hWnd on InitDialog function of this window.</font>

return 0 ;
}


MyMainDialog_OkClick()
{
hWnd = NULL ;
char data[ 3 ] ;

	HANDLE hTread = CreateThread( ... , (LPTHREAD_START_ROUTINE)MyProgressDlgThread , (LPVOID)NULL , ... ) ;
	int i = 0 , n = 10 ;
	while( i < n )
	{
		if( hWnd )
		{		
			sprintf( data ,"%d" ,  i ) ;
			ProgressFunc( hWnd , data ) ; 
		}
		Sleep( 1000 ) ;
	};

}

my problem is,
the dialogbox shown only after 2-3 seconds and the value is updated only once. how to

solve this problem ?

i cant use a timer here for some reason.

plz help me

Thanks & Regards

modified on Tuesday, December 11, 2007 2:18:28 AM

Re: Problem using sleep function.

Llasus10-Dec-07 20:11

Llasus

10-Dec-07 20:11

nitin3 wrote:
int i = 0 , n = 0 ;
while( i < n )
{
if( hWnd )
{
sprintf( data ,"%d" , i ) ;
ProgressFunc( hWnd , data , 0 ) ;
}
Sleep( 1000 ) ;
}

you're code is somewhat confusing and seems incomplete. though I saw this:

int i = 0, n = 0;
while(i < n) //0 == 0 won't enter this loop
{
}

Re: Problem using sleep function.

Llasus10-Dec-07 20:53

Llasus

10-Dec-07 20:53

looks like you've modified your post.

nitin3 wrote:
int i = 0 , n = 10 ;
while( i < n )
{
if( hWnd )
{
sprintf( data ,"%d" , i ) ;
ProgressFunc( hWnd , data ) ;
}
Sleep( 1000 ) ;
};

have you tried placing i++ inside your loop? it will be stuck inside that loop in the first place since you're not moving your counter. placing Sleep( 1000 ); inside the main thread will cause the dialog to be somewhat "stuck" because you are stopping the main thread of your application. I suggest you go for a timer or just place the process inside the thread you have created.

Re: Problem using sleep function.

Cedric Moonen10-Dec-07 21:09

Cedric Moonen

10-Dec-07 21:09

It is because messages are processed by your main thread. As your main thread is busy (you Sleep 3 times), no messages are processed during this time and your dialog is not updated. Once your function exits, messages are processed and your value is updated. It looks like only once but it is updated 3 times very fast.

You should do the opposite: keep your dialog in the main thread and put the 3 Sleep in the thread function.

Cédric Moonen
Software developer

Charting control [v1.2]

Re: Problem using sleep function.

krmed11-Dec-07 2:02

krmed

11-Dec-07 2:02

You should be able to solve this by a minor modification to your ProgressFunc:

void  ProgressFunc(HWND hwnd , char* progress )
{
	SetWindowText( hWnd , progress ) ;  //Update progress text by changing window title
	UpdateWindow(hWnd);
}

As mentioned by others, the sleep is generally not a good idea. I'm not sure why you say a timer won't work, but that's a better choice.

Hope that helps.

Karl - WK5M
PP-ASEL-IA (N43CS)
PGP Key: 0xDB02E193
PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

Windows Service Help [modified]

narayanagvs10-Dec-07 19:04

narayanagvs

10-Dec-07 19:04

Hi,

I need to create a windows service which should not be stopped unless and until I UnInstall my Program i.e it should be started automatically on startup.
I just want to know whether this is possible or not.If so how?

Any suggestions or relevant links would be helpful.

Thanks

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

modified on Tuesday, December 11, 2007 1:41:42 AM

Re: Windows Service Help

JudyL_MD11-Dec-07 3:40

JudyL_MD

11-Dec-07 3:40

narayanagvs wrote:
I just want to know whether this is possible or not.If so how?

Yes it's possible. It's the usual way a service works. Your install program uses the Service Control Manager to create the entries for an auto-start service and copies the service to the hard drive, and your uninstall program removes those entries via the SCM and removes the service from the drive.

Services[^]

Judy

explicit keyword

George_George10-Dec-07 18:58

George_George

10-Dec-07 18:58

Hello everyone,

I am reading the C++ Programming Language book, but can not find the function of explicit keyword of constructor. Could anyone explain its usage or refer some learning materials please?

thanks in advance,
George

Re: explicit keyword

Don Box10-Dec-07 19:14

Don Box

10-Dec-07 19:14