C / C++ / MFC

1-Feb-02 14:10

I've got a file browsing list control inside a custom Outlook Control. The problem is that when I remove all the items in the list control and fill them with a new list (as in the user selects a different folder to browse), a bunch of blank space gets left at the top. Below is a screenshot:

(dunno why this image doesn't want to display)

This seems about the same amount of space as the scroll offset before the list items were updated. I've tried a calling a bunch of functions to see if I can get rid of this, but can't. (The attemps are shown below under the //!!! part.

void
cPkpPhotoListControl::OnRightClick(NMHDR* pNMHDR, LRESULT* pResult)
{
cResId PopupMenuResId = GetPopupMenuResId();

//!!!
CListCtrl::SetWorkAreas(0, NULL);
CListCtrl::Arrange(LVA_ALIGNTOP | LVA_ALIGNLEFT);
CListCtrl::SetWorkAreas(0, NULL);
SetScrollPos(SB_VERT, 0);

if(!PopupMenuResId.IsVoid())
{
cPoint ScreenPoint;
GetCursorPos(&ScreenPoint);

//!!!!
cPoint sss = ScreenPoint;
ScreenToClient(&sss);

cWindowHelper Helper(this);
Helper.HandlePopupMenu(PopupMenuResId, ScreenPoint);
}

*pResult = 0;
}

Now I've hooked this into the right mouse click handler so I they are called whenever I hit the right mouse button (just for debugging).

I've also tried clicking the top of this space, and that point comes out as near 0 in client coordinates, so I know that white space is part of the list control. I can also drag a selection box in this white space.

Anyone have any ideas? Any other commands I can try?

Cheers,

Check out Aephid Photokeeper, the powerful digital
photo album solution at www.aephid.com.

Class prototype?

1-Feb-02 14:05

Such a thing as a class prototype? Im sure there is... I need to know how to use it since I have a class that needs to derive an object from another class and use it but the other class is defined after it and if i define it before it I will hit the same problem with its class.

-- Remember your are but a lowly hair on my s*r*t*m

Swinefeaster1-Feb-02 14:14

1-Feb-02 14:14

For example, the class prototype for CString would be:

class CString;

But you can only use pointers and references to a prototyped class if it's not defined yet (just declared with the prototype). So you'll have to create instances of it off the heap with the new operator, and store data members as pointers.

cheers,

swinefeaster

Check out Aephid Photokeeper, the powerful digital
photo album solution at www.aephid.com.

Tim Smith1-Feb-02 14:40

Tim Smith

1-Feb-02 14:40

And make sure you don't use the old C casting operation on pointers prior to the class being defined. That will cause nasty problems. If you use static_cast, it will error if the class hasn't been defined.

Tim Smith
Descartes Systems Sciences, Inc.

Tantalus1-Feb-02 16:30

Tantalus

1-Feb-02 16:30

new CString;
my_val = CString.whatever(); ?

-- Remember your are but a lowly hair on my s*r*t*m

Swinefeaster1-Feb-02 16:37

Re: Sort of Serialization

1-Feb-02 16:37

That doesn't make any sense.

in the header file (for example):

class CString;

class CStringUser
{
public:
CStringUser(void);

private:
CString* m_Member;
};

In the cpp file:

#include "StdAfx.h"
#include "CString.h"

CStringUser::CStringUser(void)
{
m_Member = new CString;
}

...but of course that's assuming "CString" is the class you want to forward declare.

Cheers,

swinefeaster

Check out Aephid Photokeeper, the powerful digital
photo album solution at www.aephid.com.

Sort of Serialization

1-Feb-02 14:00

Hi,

I have some data in my app which is manipulated by the user which should automagically be saved upon exit, in order to be available when launching the app next time.

The amount of data is too big for storing them in the registry so I thought they could be serialized to a file.
But I want to do it without prompting the user for a filename.

Any ideas how I could achieve this?
Thanks.

Pepe

Swinefeaster1-Feb-02 14:03

Re: Sort of Serialization

1-Feb-02 14:03

You could save it in the user's settings folder. For example, "c:\Documents and Settings\Matus\Application Data". But you should use the windows functions to make sure you are retrieving the right folders. I think its SHGetSpecialFolderLocation() or SHGetSpecialFolderPath().

Cheers,

swinefeaster

Check out Aephid Photokeeper, the powerful digital
photo album solution at www.aephid.com.

1-Feb-02 14:44

yeah, but AFAIAC the Serialize function is called by the system when the user clickes save or open in the file menu.

How can I trigger the above call without any user interaction, and how can I give the location without having to deal with CFileDialog?

Thanks
Pepe

Re: Sort of Serialization

Matt Gullett1-Feb-02 14:52

Matt Gullett

1-Feb-02 14:52

Basically, CArchive just uses a CFile object as its internal file access class. The Serialize function for your object is passed a CArchive automatically by the framework, but you can do it manually also.

----------------------------------------
to serialize your data to disk:
----------------------------------------
CFile fp;

fp.Open(somefilename,CFile::modeWrite | CFile::modeCreate | CFile::shareExclusive);

CArchive ar(&fp, CArchive::store);

obj.Serialize(ar);

ar.Close();

fp.Close();

----------------------------------------
to load data from disk
----------------------------------------
CFile fp;

fp.Open(somefilename,CFile::modeRead | CFile::shareExclusive);

CArchive ar(&fp, CArchive::load);

obj.Serialize(ar);

ar.Close();

fp.Close();

----------------------------------
to automatically determine a file name
----------------------------------
Often, what I do is to save the file in the same path as the EXE, but I use the users computer name and user-name as the file name. If I want the user to be able to log in from different computers, I just use their user name.

char szAppPath[2000];
char szDrive[200];
char szDir[200];
char szComputer[2000];
char szUser[2000];
DWORD dwTempSize = 0;
CString strFileName;

memset(szAppPath, 0, 2000);
memset(szDrive, 0, 200);
memset(szDir, 0, 200);
memset(szComputer, 0, 2000);
memset(szUser, 0, 2000);

::GetModuleFileName(AfxGetInstanceHandle(), szAppPath);
_splitpath(szAppPath, szDrive, szDir, NULL, NULL);

dwTempSize = 2000;
::GetUserName(szUser, &dwTempSize);
dwTempSize = 2000;
::GetComputerName(szComputer, &dwTempSize);

strFileName = szDrive;
strFileName += szDir;
strFileName += szComputer;
strFileName += "-";
strFileName += szUser;
strFileName += ".dat";
---------------------------------------

PS. I wrote the above code from memory so there might be some typos, etc.

Matt Gullett

CMutex

Cathy1-Feb-02 13:55

Cathy

1-Feb-02 13:55

I need to allow users to run more than one instance of my app. Unfortunately I have to use Netbios functions. I have found that my app locks up the entire machine if one instance is deleting the name from the name table at the same time the other one resetting the lanas or adding the name. So I thought I could use a mutex to have the second one wait if the first one is deleting the name. Unfortunately it doesn't seem to work. Here is the code:

CMutex mutex(TRUE, "application name - Stopping or starting network stuff");
CSingleLock lock(&mutex);
lock.Lock();

The first one exectutes this and has not exited the function (so the mutex has not been deleted) when the second one executes this. The second one does not wait.

What am I doing wrong?

Confused | :confused:

Cathy

Life's uncertain, have dessert first!

Rick York1-Feb-02 18:03

Rick York

1-Feb-02 18:03

Are you checking the return state of the Lock ?

You might want to have a look at the MUTEXES sample app from MSDN to see how to use CMutex correctly.

Cathy1-Feb-02 20:39

Cathy

1-Feb-02 20:39

Thanks. I will look at the return value to see if it failed and look at the MSDN sample. The documentation sounded pretty straitforward. I read someone's comments somewhere saying the first version of MFC's critical section class was buggy. So I thought maybe this one is too. So I was hoping to hear from someone who had used it before and could tell me whether or not it worked.

Cathy

Life's uncertain, have dessert first!

Rick York1-Feb-02 21:08

Rick York

1-Feb-02 21:08

Actually, my first attempts with it were not successful so I just wrote my own little thing using the Win32 mutex functions. They seemed a bit more straight forward to me. The API functions used are CreateMutex, WaitForSingleObject, ReleaseMutex, and CloseHandle. They are invoked in that order.

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