C / C++ / MFC Discussion Boards

Rilhas17-Jul-06 13:43

17-Jul-06 13:43

After reading these many posts (although many of them seemed to miss the point entirely) I agree with what as already been stated: the "protected" keyword in A allows access from B to protected members in B inherited from A. Not members from A.

So, there is no real way to make this access legal. B can access all the protected members of B, but not the protected members of A. I do think that this is a design error, although I believe that someone has thought about it and found enough arguments to justify this protection. I would be happy to leave it to the lawyers to argue about it.

Meanwhile, to get around the issue, you could force a static cast on the partner. For example:

struct A
{
A* partner;
void doodah()
{ ++partner->value; } //this is legal
protected:
int value;
};

struct B: public A
{
void foobar()
{ ((B*)partner)->value += 2; } //but this isn’t
};

This code compiles. You may use this code safely because you know that B contains an A. So, the static cast can be used safely if you ensure that you do not use any of B's features on the cast A's partner pointer.

Anyway, with the static cast solution, you can keep the value protected, and still use it from inside B. The code in foobar() is the only one accessing the "value" (this gives you a "per line" control, as oposed to class or function access provided by the use of "friend").

I hope this helps (although I'm sure you will see it as a workaround, I know I do),
Rilhas

Re: overzealous protection rules

David Crow31-Jul-06 10:28

David Crow

31-Jul-06 10:28

Note that for "plain value" the compiler knows that the value is a member of a B; for "partner->value" it only knows that value is a member of an A.

There is a rule that says that "protected" gives access only to a base of an object of "your own class." That rule was introduced after some pretty horrific bugs appeared where the equivalent to "partner" in your code pointed to a completely different class C that just happened to have the same base (A). There is a discussion of this in D&E.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

A (simple) Shell Question

Dave Kerr12-Jul-06 4:49

Dave Kerr

12-Jul-06 4:49

Hi,

I am currently writing a namespace extension. I have an IShellFolder implementation, that implements such functions as 'SetNameOf' (called when the user renames an item). However, after calling SHChangeNotifiy (with PIDLs fully qualified, i.e relative to the desktop) my IShellView DOESN'T refresh the changes.

I haven't implemented my own IShellView, I use one created by SHCreateShellFolderView. I would imagine this IShellView would automatically respond to SHChangeNotify, but it doesn't. If I force a refresh by hitting F5 the correct renamed file is then displayed.

Does anyone have any ideas as to why SHChangeNotify isn't working? Any help would be appreciated.

Many thanks,

Dave

Dave Kerr
codechamber@hotmail.com
http://www.codechamber.com

Labeling Slider Bar stops

LCI12-Jul-06 4:36

LCI

12-Jul-06 4:36

Is there any way to label the stops on a slider control?
E.g.

| | |

-1 0 1

Re: Labeling Slider Bar stops

pgrohs12-Jul-06 4:51

pgrohs

12-Jul-06 4:51

Yes, you have to draw it your own.

Re: Labeling Slider Bar stops

LCI12-Jul-06 5:51

LCI

12-Jul-06 5:51

Would this be done using owner draw?

Re: Labeling Slider Bar stops

pgrohs12-Jul-06 6:05

pgrohs

12-Jul-06 6:05

Exactly!

RightToLeft property

Elbaz Haviv12-Jul-06 3:17

Elbaz Haviv

12-Jul-06 3:17

I have a dialog based app with a control edit in it.
orginaly writen in vc6 and upgraded to .NET/winxp
How I can Set the RightToLeft property for the edit
cotrol on/off at run time.

I'm vary THANK YOU in advanced.

Elbaz Haviv

Elbaz Haviv

Re: RightToLeft property [modified]

includeh1012-Jul-06 3:33

includeh10

12-Jul-06 3:33

i have some expeirence with combo-box.
styles of combo-box can not be changed at run time (i.e. from DropDown to DropDown-list).
so when I needed to change its style, I deleted the control then created a new one - looks not good but it worked fine.

I never use edit in your way, but u may use my idea if modification at run time is not possible.

-- modified at 9:36 Wednesday 12th July, 2006

Re: RightToLeft property

David Crow12-Jul-06 4:36

David Crow

12-Jul-06 4:36

Not all styles can be changed at run-time. You can try ModifyStyle() to see if it works in this situation. You may find it easier to have two edit controls on the dialog template, one with the WS_EX_LTRREADING style and the other with the WS_EX_RTLREADING style. Then just show/hide the controls accordingly.

"The largest fire starts but with the smallest spark." - David Crow

"Judge not by the eye but by the heart." - Native American Proverb

Localization in Input String and Log files.

karthik Tamizhmathi12-Jul-06 3:11

karthik Tamizhmathi

12-Jul-06 3:11

Dear all,

I need to re-engineer a very big existing source code(Mostly Non-MFC) for localization support.

For that the user input strings should be capable of support in the native language character set throughout the project.

Moreover i have to translate the log files in to regional language based on the language selection.

Kindly refer the Ted's article.
http://www.codeproject.com/cpp/mult_lang_support.asp[^]
Kindly suggest me in this regard.
Regards,

Karthik M

How to write KeyboardProc()

Max++12-Jul-06 3:09

Max++

12-Jul-06 3:09

About Keyboard Hook
If I want my program can get the key more than one key such as Ctrl+Shift+Z before execute some command.
How to write the code in KeyboardProc() function.

Re: How to write KeyboardProc()

includeh1012-Jul-06 3:22

includeh10

12-Jul-06 3:22

GetKeyboardState() can get states of 256 keys at same time.

Items appear twice in 'Find' results

LittleYellowBird12-Jul-06 3:00

LittleYellowBird

12-Jul-06 3:00

When I perform a 'Find' in my current VS2005 project, some of the files in my project get searched twice. So a word which occurs once in that file appears as two identical results from the 'find'.

Anyone know why? Can I clear it somehow?

Thanks for any suggestions Smile | :)

Ali

can ChooseFont use ChooseColor?

includeh1012-Jul-06 2:42

includeh10

12-Jul-06 2:42

ChooseFont or CFontDialog has few of colors, I want to change font color by ChooseColor or CColorDialog when CFontDialg is displaying, is it possible?

Re: can ChooseFont use ChooseColor?

_AnsHUMAN_ 12-Jul-06 5:03

_AnsHUMAN_

12-Jul-06 5:03

I did this OnOK Button of a dialog

CColorDialog *cDlg=new CColorDialog();
COLORREF myColor;
if(IDOK==cDlg->DoModal ())
{
	myColor=cDlg->GetColor ();
}
HDC hdc=::GetDC(m_hWnd);
SetTextColor (hdc,myColor);
TextOut (hdc,10,100,"hello",5);
::ReleaseDC(m_hWnd,hdc);

Somethings seem HARD to do, until we know how to do them.
Wink | ;-)

_AnShUmAn_

Re: can ChooseFont use ChooseColor?

includeh1012-Jul-06 5:45

includeh10

12-Jul-06 5:45

u just made my post sick!

Comunicating Gina with user mode App or service

Kharfax12-Jul-06 2:25

Kharfax

12-Jul-06 2:25

Hi
There is any way to communicate events, lets say "user loged in", "user logged off", from the GINA to a user mode App or service?

I mean, I know that I can write a file, or a registry key, and my app can read the info from there but I was looking for other way.

Thanks a lot people

Sebastian

Re: Comunicating Gina with user mode App or service

Steve S12-Jul-06 3:07

Steve S

12-Jul-06 3:07

If it was a usermode app, how would it get started before GINA for the first login after a reboot?

You could use shared memory, but you might want to think about what security descriptor to put on it, depending on what you actually write into it. ISTR that the late lamented Windows Developer Journal had a set of articles about communicating logon/logoff to apps.

Steve S
Developer for hire

Re: Comunicating Gina with user mode App or service

Kharfax12-Jul-06 3:16

Kharfax

12-Jul-06 3:16

Yeap I understand what you mean Steve, the login couldn't be handled that way...
I don't like the shared memory because that means a usermode app also is going to be able to modify data in the Gina, and that's not good at all.
I'll try to find those articles you talk about.

Thanks a lot Big Grin | :-D

Re: Comunicating Gina with user mode App or service

Kharfax12-Jul-06 3:29

Kharfax

12-Jul-06 3:29

I have found a great supported way, maybe in the future this will be usefull for someone.
Just google "Winlogon Notification Package"

Re: Comunicating Gina with user mode App or service

Kharfax12-Jul-06 9:58

Kharfax

12-Jul-06 9:58

F***ing useless, Vista doesn't support this

Member Function [modified]

ashish dogra12-Jul-06 2:21

ashish dogra

12-Jul-06 2:21

hi
tell me some function in mfc with example as i want to know a member function daily as i am new to vc++
thanks

Ashish Dogra
MCA
Noida

-- modified at 9:11 Wednesday 12th July, 2006

Re: Member Function

Abhi Lahare12-Jul-06 2:28

Abhi Lahare

12-Jul-06 2:28

what do you mean by Super Function?

Re: Member Function

ashish dogra12-Jul-06 2:37

ashish dogra

12-Jul-06 2:37

super means any good function that help me alot and with which something interstig thing can be handled
thanks for ur reply

Ashish Dogra
MCA
Noida

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