C / C++ / MFC

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

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

BrowseFolders Dialog on Win2k/IE5?

26-Apr-05 17:51

See SetupIterateCabinet[^]

PeterRitchie.com

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

Peter Ritchie26-Apr-05 17:20

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

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

Peter Ritchie29-Apr-05 5:26

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

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

PJ Arends26-Apr-05 11:17

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

Anonymous26-Apr-05 11:27

Anonymous

26-Apr-05 11:27

It's how COM object lifetime is managed. Last one to call Release(), essentially tells the object to delete itself. For instance:

ULONG Release(void)
{
    ULONG lResult = InterlockedDecrement(&m_dwRef);
    if (lResult == 0) delete this;
    return lResult;
}

Steve Messer26-Apr-05 12:02

Steve Messer

26-Apr-05 12:02

Okay so COM makes use of it and also with self deleting classes.

I understand the COM aspect but what is a self deleting class?

Let me clarify the question a little. Is there a general rule? When would you use delete this?

Thanks

PJ Arends26-Apr-05 12:16

26-Apr-05 12:16

smesser wrote:
what is a self deleting class?

A class that deletes itself. Examples are CFrameWnd and CWinThread (when m_bAutoDelete is TRUE).

"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

Steve Messer26-Apr-05 12:28

Steve Messer

26-Apr-05 12:28

Yeah, but that is framework stuff. When as a programmer have you used:

delete this;

Steve

PJ Arends26-Apr-05 12:54

26-Apr-05 12:54

http://www.codeproject.com/miscctrl/windowscroller.asp[^]

"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

Maximilien26-Apr-05 12:10

Maximilien

26-Apr-05 12:10

with MFC, it's used to delete a modeless dialog.

Maximilien Lincourt
Your Head A Splode - Strong Bad

Brian R26-Apr-05 12:45

Brian R

26-Apr-05 12:45

I have been programming with c++ since the Cfront "compiler" came out of ATT. I have never found a circumstance where delete this seemed like a correct solution. My impresssion is that it is an artifact of bad design. The fact that the MFC and COM implementation require it is not a surprise Wink | ;-)

Along the same line, throwing an exception via a pointer is equally dangerous in my book!

PJ Arends26-Apr-05 13:21