C / C++ / MFC Discussion Boards

File I/O : Which one to use? CFile or fstream?

jahfer26-Apr-05 19:36

26-Apr-05 19:36

Hello,

I am working with VC++ 6.0 (MFC).

I need to write the following structure to a file in binary mode.

struct EmployeeData
{
char strName[50];
UINT nAge;
float fSalary;
};

For that, which class that I will use? CFile or fstream?

TIA,

Regards,
Jahfer V P

Re: File I/O : Which one to use? CFile or fstream?

stolid_rock26-Apr-05 19:51

stolid_rock

26-Apr-05 19:51

I suggest you should use the CFile rather than fstream. You can do lots of things using the functionality CFile provides

Re: File I/O : Which one to use? CFile or fstream?

jahfer26-Apr-05 19:54

jahfer

26-Apr-05 19:54

Dear Stolid_rock,

Can you give any sample code doing this?

Regards,
Jahfer V P.

Re: File I/O : Which one to use? CFile or fstream?

stolid_rock26-Apr-05 20:34

stolid_rock

26-Apr-05 20:34

You can get some basic implementations at
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore98/HTML/_core_files_in_mfc.asp
and
http://www.codersource.net/mfc_cfile.html

Re: File I/O : Which one to use? CFile or fstream?

Ravi Bhavnani27-Apr-05 2:18

Ravi Bhavnani

27-Apr-05 2:18

See this[^] series of articles.

/ravi

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How do I save/load STL data (map & vector)

Larry Mills Sr26-Apr-05 15:35

Larry Mills Sr

26-Apr-05 15:35

Can someone show me how to send (save/Write) and receive (load/Read) data contained in a map and/or vector. class CData{ public: string one, two, three; CData() {}; ~CData() {} };

the map is declared as: map<string CData> DATA; How do I read/write it's data to a file ("MyMapFile.dat") ???

vector<CData> vecDATA; how do I read/write it's data to a file("MyVecDATA.dat") ???

I'm new to the STL and would need explicit examples that are known to work properly PLEASE.

C++ is my favorite programming language

Re: How do I save/load STL data (map & vector)

Nemanja Trifunovic26-Apr-05 16:51

Nemanja Trifunovic

26-Apr-05 16:51

Take a look at Boost Serialization[^] library.

My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.

Re: How do I save/load STL data (map & vector)

CP Visitor26-Apr-05 22:50

CP Visitor

26-Apr-05 22:50

"Boost Serialization" certainly is the right library for someone "new to the STL". Mad | :mad:

Better give no answer than one that is not helpful.

Need some advice - header file issues

Yguy26-Apr-05 14:09

Yguy

26-Apr-05 14:09

I have a project where I'm including a file that's not part of the project (VC++ 6.0). The file is located in a directory specified in the VS include and source directory options. I include the H file in my project using <#include fname.h>, the respective CPP file contains no templates or or macros, and the code is C++ - there are no C function calls. When I compile I get linker 2001 errors. However, if I import the H and CPP files into the project (add to project) it compiles fine. It also compiles fine if I leave the files out of the project and place the code from the CPP file into the H file. Can anyone clue me in as to what's going on here? Thanx Confused | :confused:

Woman...you can't live with them, you can't live with them.

Re: Need some advice - header file issues

PJ Arends26-Apr-05 15:23

PJ Arends

26-Apr-05 15:23

The compiler has to able to find all the functions it needs in order to build your program. There are two ways that it does this. First is to look through all the files that are in the project (add to project) or it tries to find them in any libraries that are attached to your project.

What the #include directive does is inserts the code from the included file into the file that it is included in, just as if you had typed the code there yourself. So to the compiler it looks as if the code is part of the file, and thus it finds it through the first method.

If you do not want to add the cpp file to your project, you can #include it in another cpp file that is part of your project just as you would a header file. Just be sure to do this only once, or else you will get other errors.

"You're obviously a superstar." - Christian Graus about me - 12 Feb '03

"Obviously ??? You're definitely a superstar!!!" mYkel - 21 Jun '04

Within you lies the power for good - Use it!

Honoured as one of The Most Helpful Members of 2004

I figured it out...

Yguy26-Apr-05 15:30

Yguy

26-Apr-05 15:30

I needed to compile the CPP file seperately, and add the resulting OBJ file to the LIB/OBJ files to be linked to the project. I actually have 3 seperate classes in 3 seperate files that do not reside in the project, so I decided to bundle them up in a LIB.

My bad for asking in the first place, but I must've lost more brain cells in the '70s than I realized. Blush | :O

I'm going to leave this here in case someone else runs into this issue sometime down the road.

IDE's are convenient, but they sure do make it easy to forget what goes on behind the scene.

Re: I figured it out...

Rick York27-Apr-05 6:14

Rick York

27-Apr-05 6:14

Personally I think it is bad practice to configure the IDE with include and library directories. This requires anyone else who uses (develops with) your code to have the same configuration. I believe that it is preferable to configure those for each project and/or solution.

IE Form Filler

Krazyman26-Apr-05 11:59

Krazyman

26-Apr-05 11:59

I was recently given a project to write a program to fill forms on the company web site. the program collects data and sits idle , when the web site is accessed the program will automaticaly fill the forms with with correct data. all i have left is the form fill part but i can't find any leads on how to do this. could someone point me in the right direction as to how this is done.

Re: IE Form Filler

Michael Dunn26-Apr-05 12:16

Michael Dunn

26-Apr-05 12:16

You can write a BHO that watches for the NaviagateComplete event, then checks either the URL (for example, if you know the forms will always be on your company's site) or just looks for HTML elements with the right names/ids.

--Mike--
Visual C++ MVP Cool | :cool:

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Image Printing

Member 94915926-Apr-05 11:54

Member 949159

26-Apr-05 11:54

I am trying to print a bmp image in MFC. I have tried creating a memory DC (compatible with the printer) and using BitBlt but it doesn't work for a printer DC. I have also tried CreateCompatibleBitmap which may work but how do I get the image into the newly created bmp. I tried using SetBitmapBits but no success. Obviously there is more preparations to do for this to work. Anyone done this before?

Re: Image Printing

Peter Ritchie26-Apr-05 17:48

Peter Ritchie

26-Apr-05 17:48

In your CView-derived class's OnDraw:

CBitmap bmp;
if (bmp.LoadBitmap(IDB_BITMAP1))
{
   // Get the size of the bitmap
   BITMAP bmpInfo;
   bmp.GetBitmap(&bmpInfo);

   // Create an in-memory DC compatible with the
   // display DC we're using to paint
   CDC dcMemory;
   dcMemory.CreateCompatibleDC(pDC);

   // Select the bitmap into the in-memory DC
   CBitmap* pOldBitmap = dcMemory.SelectObject(&bmp);

   // Find a centerpoint for the bitmap in the client area
   CRect rect;
   GetClientRect(&rect);
   int nX = rect.left + (rect.Width() - bmpInfo.bmWidth) / 2;
   int nY = rect.top + (rect.Height() - bmpInfo.bmHeight) / 2;

   // Copy the bits from the in-memory DC into the on-
   // screen DC to actually do the painting. Use the centerpoint
   // we computed for the target offset.
   pDC->BitBlt(nX, nY, bmpInfo.bmWidth, bmpInfo.bmHeight, &dcMemory,
      0, 0, SRCCOPY);

   dcMemory.SelectObject(pOldBitmap);
}

PeterRitchie.com

system files

trupgmtuf26-Apr-05 11:46

trupgmtuf

26-Apr-05 11:46

Hi,
In my program I need a windows system file say mouhid.sys, for example.
I found that file inside the cab file in windows\driver cache\i386\driver.cab. If I give this as my source path in my program, it is not detecting the file( I think because of cabinet file).
Is there any way to tell the system to take from that cab file automatically or any spl path that we can mention so that the system automatically detects the file.
Thanks a lot.

Re: system files

Peter Ritchie26-Apr-05 17:51

Peter Ritchie

26-Apr-05 17:51

See SetupIterateCabinet[^]

PeterRitchie.com

BrowseFolders Dialog on Win2k/IE5?

Ingmar326-Apr-05 11:07

Ingmar3

26-Apr-05 11:07

Hello,

I've got a class to browse folders similiar to CSXBrowseFolder here on code-project. It worked fine until I needed to run my software on a fresh installed Windows 2000 with IE5.
Selecting e.g. "My Documents" gives me not the real path but an Id like "::{xxxxxxxxx}".
I'm not sure if I'm right, but I think I need to resolve this "link" using the shell functions. But whatever I tried it didn't work.
If I select a usual folder (e.g. c:\test) it works like expected.

I found a message on MSDN, that win2k/ie5 doesn't follow these links. But newer versions do so. Seems I get the Id of the not real existing folder, while IE6 resolves these links automatically.

Maybe someone can give me hint how to solve this problem? Thanks in advance!
Ingmar

Re: BrowseFolders Dialog on Win2k/IE5?

Peter Ritchie26-Apr-05 17:20

Peter Ritchie

26-Apr-05 17:20

You can convert the file object's display name into a path with the following:

<FONT COLOR=GREEN>/// <summary>
/// Sample that converts a textual file/folder object display name
/// (::{GUID} format) to a physical path (if possible)
/// </summary>
/// <author> Peter A. Ritchie</author>
/// <date type="creation">26-Apr-2005</date>
</FONT>CComPtr<FONT COLOR=BLUE><</FONT>IShellFolder<FONT COLOR=BLUE>></FONT> pshf <FONT COLOR=BLUE>=</FONT> NULL<FONT COLOR=BLUE>;</FONT>

<FONT COLOR=BLUE>:</FONT><FONT COLOR=BLUE>:</FONT>SHGetDesktopFolder<FONT COLOR=BLUE>(</FONT><FONT COLOR=BLUE>&</FONT>pshf<FONT COLOR=BLUE>)</FONT><FONT COLOR=BLUE>;</FONT>
LPITEMIDLIST pidlDocFiles<FONT COLOR=BLUE>;</FONT>
ULONG cbEaten<FONT COLOR=BLUE>;</FONT>
pshf<FONT COLOR=BLUE>-</FONT><FONT COLOR=BLUE>></FONT>ParseDisplayName<FONT COLOR=BLUE>(</FONT>NULL<FONT COLOR=BLUE>,</FONT> <ul>	NULL<FONT COLOR=BLUE>,</FONT> 
	L<FONT COLOR=PURPLE>"::{450d8fba-ad25-11d0-98a8-0800361b1103}"</FONT><FONT COLOR=BLUE>,</FONT> 
	<FONT COLOR=BLUE>&</FONT>cbEaten<FONT COLOR=BLUE>,</FONT> 
	<FONT COLOR=BLUE>&</FONT>pidlDocFiles<FONT COLOR=BLUE>,</FONT> 
	NULL<FONT COLOR=BLUE>)</FONT><FONT COLOR=BLUE>;</FONT>
</ul>
TCHAR szPath<FONT COLOR=BLUE>[</FONT>MAX_PATH<FONT COLOR=BLUE>]</FONT> <FONT COLOR=BLUE>=</FONT> _T<FONT COLOR=BLUE>(</FONT><FONT COLOR=PURPLE>""</FONT><FONT COLOR=BLUE>)</FONT><FONT COLOR=BLUE>;</FONT>

<FONT COLOR=BLUE>:</FONT><FONT COLOR=BLUE>:</FONT>SHGetPathFromIDList<FONT COLOR=BLUE>(</FONT>pidlDocFiles<FONT COLOR=BLUE>,</FONT> szPath<FONT COLOR=BLUE>)</FONT><FONT COLOR=BLUE>;</FONT>

But, I'm curious, how are you getting the display name "::{GUID}"? Are you using SHBrowseForFolder? If so, what are you doing with the PIDL?

PeterRitchie.com

Re: BrowseFolders Dialog on Win2k/IE5?

Ingmar326-Apr-05 21:18

Ingmar3

26-Apr-05 21:18

Thanks for the help. I tried it out, but if gives me the same GUID back again I put in?!

For your question, I use
itemIDList = SHBrowseForFolder(&browseInfo);
...do some checks and then
SHGetPathFromIDList(itemIDList, szPathBuffer);

And at this point I've got that GUID in szPathBuffer. I found so many samples, everyone does it that way, but I already tested on 2 win2k machines and it doesn't work. (Except I update to IE6, but this is currently not an option).
Maybe something is wrong with my browseinfo structure? I did nothing special, maybe some flags are needed I didn't set?

Ingmar

Re: BrowseFolders Dialog on Win2k/IE5?

Peter Ritchie29-Apr-05 5:26

Peter Ritchie

29-Apr-05 5:26

Then you've got a GUID to a virtual folder that does not have a physical location for it.

PeterRitchie.com

Re: BrowseFolders Dialog on Win2k/IE5?

Ingmar313-May-05 1:40

Ingmar3

13-May-05 1:40

I tested some things, and it seems the problem isn't SHBrowseForFolder itself. But it's more strange: A simple BrowseForFolder-application works well on 2k, but my real application doesn't! I did try and error and I found out, that I get a good path, when I run SHBroswForFolder before I open a database via ODBC (CDatabase) ?!?!

Don't have a good idea now, but it has definitly to do with the DB-Open. Maybe it's a bug? This works great on XP or better on any machine with IE>5.

Ingmar

delete this questions

Steve Messer26-Apr-05 10:42

Steve Messer

26-Apr-05 10:42

It is my understanding the using the following line of code is bad pratice.

delete this;

Is there ever a good reason to use this construct?

Thanks

Re: delete this questions

PJ Arends26-Apr-05 11:17

PJ Arends

26-Apr-05 11:17

Like anything else, if it is used properly it has its uses, but used improperly it can be disatrous. I use it for classes that are to be self deleting, and always make sure it is the very last command the class executes.

"You're obviously a superstar." - Christian Graus about me - 12 Feb '03

"Obviously ??? You're definitely a superstar!!!" mYkel - 21 Jun '04

Within you lies the power for good - Use it!

Honoured as one of The Most Helpful Members of 2004

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