C / C++ / MFC

Re: 840723 - overriding an MFC function

14-Oct-05 22:25

I believe that you can define your own function with the same name and parameters and return type as the original one, when your class is a descendent of the class whose function you want to override, provided that that function is not internally called by the MFC libraries.

Maybe someone can shed some light on my thoughts above.

If you wanted to override a function for lets say CDialog, then you would subclass it, and implement your own function. But I believe that that function should be in CDialog, not in its some parent in the hierarchy, used by its some other parent, to be effective.

this is this.

ilostmyid215-Oct-05 2:00

ilostmyid2

15-Oct-05 2:00

thanx khan for answering me.
let's discuss about ur answer!
1. it's better to use "derived" word. instead of "when your class is a descendent of the class whose function you want to override" it's better to say "when ur class is derived from the class whose function..."
2. when a function is declared as virtual, if it's overriden in the derived class, functions of the base class see it and call it instead of the original one (the function in the base class) while they may think they're really calling the original one.
if the function is not declared as virtual in the base class both classes have their own function with the same prototype. that is functions of base class when call it call the function of base class and function of the derived class when call it call the function of the derived class.
this is what the "virtual" keyword provides.
3. what do u mean by subclassing?
4. u may also use "base" instead of "parent"
i remind my question again. i'm looking for a way for functions of base class to call the function i write instead of what they're linked to. when this member function is not declared as virtual this sounds impossible, but i think there must be a way. besides, there may be a function not belonging to any class and i need to override it.
this may be a linker option or so that when encounters an ambiguity decides which one to use. normally it ignores my code and uses one defined in MFC itself.
when i was programming with BC++ or TC++ some years ago, the linker prefered my code over the original one.
and khan! English seems not to be ur mother tongue like me! Wink | ;)

thanks again for ur appreciate and also waiting for other answers

convert cstring to int

cell5114-Oct-05 21:01

cell51

14-Oct-05 21:01

i new in use mfc grid control by CMaunder Smile | :)

it default cell type is CString, i want to process cell value as int, can some one help me to conver CString to int, or any other sugestion?

Prakash Nadar14-Oct-05 21:09

Prakash Nadar

14-Oct-05 21:09

msnet wrote:
CMaunder

makes a good class name. Laugh | :laugh:

-prakash

The NULL Developer14-Oct-05 21:17

The NULL Developer

14-Oct-05 21:17

This might help u:

<br />
CString str = "123";<br />
int	i = atoi( str );<br />

John R. Shaw14-Oct-05 21:18

John R. Shaw

14-Oct-05 21:18

CString str;
// do some thing, like load data into string
int i = _ttoi(str.GetBuffer(str.GetLength()));
str.ReleaseBuffer();
// do some thing with i

I should be that simple.

Note: _ttoi() is the MICROSOFTS specific version of atoi(), it is used to support both MBCS and UNICODE.

INTP
Every thing is relative...

khan++14-Oct-05 21:19

14-Oct-05 21:19

I have not seen the article, but,
to get the integer from a char array or CString:

int i;<br />
CString str;<br />
str = "12345";<br />
i = atoi(str);

this is this.

File Handle(very urgent)

swaapu14-Oct-05 20:59

swaapu

14-Oct-05 20:59

HI!
I have used the GetModuleFileName function in my MFC SDI application. The syntax is:

DWORD GetModuleFileName(
HMODULE hModule, // handle to module
LPTSTR lpFilename, // path buffer
DWORD nSize // size of buffer
);

Parameters
hModule
[in] Handle to the module whose path is being requested. If this parameter is NULL, GetModuleFileName retrieves the path for the current module.

Now, the problem is with the HModule parameter. But, I don`t know how to set the handle to the module or file. What type of variable to declare. NULL is not serving my purpose.
Thanx

khan++14-Oct-05 21:17

14-Oct-05 21:17

Your question is not very clear. Anyway,
If you want to get the filepath of the current exe file, then you can set it to NULL:

char str[MAX_PATH];<br />
GetModuleFileName(NULL,str,MAX_PATH);

Will get the current exe's path.

If you want the path for another file, like a DLL, then when you load it using

HMODULE hModule;<br />
hModule = LoadLibrary(...)

, its handle is returned. This is the same handle for use with GetModuleFileName(...).

this is this.

swaapu14-Oct-05 23:16

swaapu

14-Oct-05 23:16

Hi!
I hav an MFC SDI Application with two dialogs. One is for selecting source file and the other is for selecting destination file. BOth, dialogs have one edit box for browsing or editing the path of file.

Actually, I don`t want to get the path of current exe. Instead, I want to get the file path from edit box of another file. I want to get the path , which was entered in the edit box for file name on the SelectSource dialog.
Thanx a lot.

khan++14-Oct-05 23:38

14-Oct-05 23:38

How are you creating both the dialogs?
If they are in the parent:

CDialog1* m_pDialog1;<br />
CDialog2* m_pDialog2;

Then you can include a pointer to the parent in dialog1:
CParent* m_pParent; //in dialog1.h

And have it initialized by the parent after the dialog creation:

m_pDialog1 = new CDialog1....<br />
.....<br />
m_pDialog1->m_pParent = this;

Then inside CDialog1:
m_pParent->m_pDialog2->m_strFileName; //whatever the variable names are.
So you can access the dialog2 from dialog1.

I hope it is clear.

this is this.