Re: how can i handle file commands to read and write xml files - C / C++ / MFC Discussion Boards

On a window i can't go on drawing pictures or lines with pen and brush
memory leak comes when number of graphical components on the screen increases
is there any possible solution to this ?
though the memory for an application is alloted by system itself, how can we use it efficiently as in this case ?

parag

By making sure you don't leak memory. When you select a pen or brush into a DC, a CPen* or CBrush * is returned and must be caught/selected back before the DC is deleted.

CPen* pOld = DC.SelectObject(&myPen);
//draw some stuff
DC.SelectObject(pOld); // Now the memory leak is taken care of.

Christian

#include "std_disclaimer.h"

People who love sausage and respect the law should never watch either one being made.

The things that come to those who wait are usually the things left by those who got there first.

I have a Dialog Box "AAA" which consists of a command button ( let's say "DISPLAY" ).
On clicking this button another dialog box "BBB" is displayed which consists of a CListctrl among others.

Now, I wanted to catch a notification when ever the item is changed.

So, I implemented the
OnNotify (LVN_ITEMCHANGED,IDC_LISTCTRL, FnHandler) like this :

void CClass :: OnItemCHanged(NMHDR* pNMHDR, LRESULT* pResult )
{
NM_LISTVIEW* pNMListView = ( NM_LISTVIEW)pNMHDR;
int len = 0;
LPTSTR str;
myListCtrl.GetItemText(pNMListView ->iItem, 2, str, len)
*pResult = 0;
}

Now, Coming to my doubt, when i try to debug with the break point inside this function, I observe that it breaks when I click the button DISPLAY. why's this when I haven't changed the state of the item yet, also, the application crashes saying "User BreakPoint Exception" after teh GetItemText call. I do see an error saying that " HEAP ALLOCATION EXCEEDED".

what's wrong in the whole issue.

PL. explain.

regards
Sankar

Your bug is that you don't allocate any space to hold the text. You pass an uninitialized pointer (str). And you give the buffer length as 0.

--Mike--
http://home.inreach.com/mdunn/
#include "buffy_sig"

when i try to debug with the break point inside this function, I observe that it breaks when I click the button DISPLAY.

LVN_ITEMCHANGED gets sent whenever any property of an item changes, including when an item is added/deleted to/from the list. If you want to act only when the selection changes, compare the old and new states of the item (which are sent with the message) and act only if their LVIS_SELECTED bits are opposite.

--Mike--
http://home.inreach.com/mdunn/
#include "buffy_sig"

Hi
I serialized my data in an xml file but how can I open or save them using
Document view architecture.I want to read data from document and use it in view.
I will be glad if I get a clear answer.
Thanks
Pathi Gorantla

bhikshapathi_g@semanticspace.com

You have to override CDocument::OnOpenDocument and CDocument::OnSaveDocument. Do not call base class implementaion - just open your own file and read/write.

Tomasz Sowinski -- http://www.shooltz.com.pl

Yeah I am trying to override OnOpenDocument() but i cant get the data from file into the document.I declared DISPPARAMS pointer in document and trying to get the data read from file into this pointer but getting an error.my aim is to read from file and show it in view.
my code is
void componentView::fileOpen()
{
isFileOpen=true;
CFileDialog file(true,
NULL, NULL,
OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,
NULL, GetParent());
file.DoModal();

CString filep=file.GetPathName();
BSTR filepath;
TCHAR szStringRepresentation[200];
wsprintf ( szStringRepresentation, _T("%s"), filep );
filepath=_bstr_t(szStringRepresentation) ;

CClientDC cdc(this);
CPen penStroke(PS_SOLID, 1, RGB(0,0,0));

cdc.SelectObject(&penStroke);

parse pa;

DISPPARAMS var=pa.readFile(filepath);

DISPPARAMS *params;
params=&var;
VARIANT myVars[2];
VariantInit(&myVars [0]);
myVars[0].vt=VT_ARRAY|VT_I4;
myVars[0]=params->rgvarg[0];
VariantInit(&myVars [1]);
myVars[1].vt=VT_ARRAY|VT_I4;
myVars[1]=params->rgvarg[1];
SAFEARRAY* SXArray;
SAFEARRAY* SYArray;
SXArray=myVars[0].parray;
SYArray=myVars[1].parray;
long lxbound,lybound;
long uxbound,uybound;
SafeArrayGetLBound(SXArray,1,&lxbound);
SafeArrayGetUBound(SXArray,1,&uxbound);
SafeArrayGetLBound(SYArray,1,&lybound);
SafeArrayGetUBound(SYArray,1,&uybound);

VARIANT ptVar;
VariantInit(&ptVar);
ptVar.vt=VT_BSTR;

int i,j,k,l;
for(long p=lxbound;p<=uxbound;p++)
{
SafeArrayGetElement(SXArray,&p,(&ptVar.bstrVal));
i=strtol(_bstr_t(ptVar.bstrVal),NULL,10);
SafeArrayGetElement(SYArray,&p,(&ptVar.bstrVal));
k=strtol(_bstr_t(ptVar.bstrVal),NULL,10);
p++;
SafeArrayGetElement(SXArray,&p,(&ptVar.bstrVal));

j=strtol(_bstr_t(ptVar.bstrVal),NULL,10);
SafeArrayGetElement(SYArray,&p,(&ptVar.bstrVal));
l=strtol(_bstr_t(ptVar.bstrVal),NULL,10);

cdc.MoveTo(i,k);
cdc.LineTo(j,l);
}

}
I did in view but how can I read file in document and draw the lines in view?

bhikshapathi_g@semanticspace.com

> I did in view but how can I read file in document and
> draw the lines in view?

You should read the file in OnOpenDocument and store the data in your document class. Use this data in overrided OnDraw in view class and draw whatever you want.

Tomasz Sowinski -- http://www.shooltz.com.pl

Hi!!!

I need to send a keysrtoke to another application. There is no problem if I simply send a key (for example F2). The problem appears if I want to send a key combination like Ctrl+F2 Frown | :(

Prease, help me!!!
SOS!!!

Thank you for your attention.

You're gonna want to look up SendInput API function... Basically build an array of INPUT strcutures with (using virtual key codes) control down, f2 down, f2 up, control up. Then BlockInput (TRUE), stick that array into SendInput and fire it off, then BlockInput (FALSE).

It should work semi decent in NT/2k, but in 98, things get sh*tty if your INPUT array contains more than 75 fields... Still haven't gotten around that... Good luck

--
Peace,
Amit Jain

I am writing a payroll software...I am having problem in print preview..... I can print preview if use 17 inch monitor but if i use the 14 inch monitor all the text are miss placed...
Why????

okie

Because you're printing to too big a size. Your 14 " monitor no doubt is running at a lower resolution than your 17 ".

Are you printing relative to the size of your printed page ? Are you working out how big the page is ?

Christian

#include "std_disclaimer.h"

People who love sausage and respect the law should never watch either one being made.

The things that come to those who wait are usually the things left by those who got there first.

Even when I change the resolution the same thing happens....I already check the page setting its A4 size.....

okie

Wait a minute - no matter what the screen resolution, the page doesn't fit on a 14" monitor and it does on a 17" monitor ? I think it's time for some details, like the resolutions you've used, some code, etc.

Christian

#include "std_disclaimer.h"

People who love sausage and respect the law should never watch either one being made.

The things that come to those who wait are usually the things left by those who got there first.

I am new to C++ and am self-teaching myself. I am trying to build a console app to perform several operations. One is the get the username. I keep getting an ERROR 122 (ERROR_INSUFFICIENT_BUFFER).

Can anyone look at my code and give assistance?

Here is my code:
================

char lpBuffer[256] = {0};
unsigned long nSize;
long lRetCode;
.
.
.
int GetUsrName()
{
lRetCode = GetUserName(lpBuffer,&nSize);
lRetCode = GetLastError();
if (lRetCode != ERROR_SUCCESS) {
LastError();
}
return (0);
}

Confused | :confused:

According to the documentation, nSize recieves the size of the buffer required - have you checked this value ?

Christian

#include "std_disclaimer.h"

People who love sausage and respect the law should never watch either one being made.

The things that come to those who wait are usually the things left by those who got there first.

You must initialize nSize with the size of your buffer (256) before calling GetUserName().

Hy!

Actualy the 'nSize' parameters is an in/out parameter. This mean that when the function s called it should contain the size of the buffer in witch user name will be stored and when the function return it will contain the real number of characters contained in user name

Bye,
Orbital

I have made changes to the code and it now returns the Username however, I also now get a different error: (997) ERROR_IO_PENDING.

Here is the new code:

TCHAR lpBuffer[256];
unsigned long nSize = 256;
.
.
.
GetUserName(lpBuffer,&nSize);
printf("UserName:\t%s\n",lpBuffer);

Try this one:

char UserName[MAX_USERNAME_LEN];
DWORD len = MAX_USERNAME_LEN; GetUserName(UserName, &len);

Hope this helps

Hi all,
Do C++ got Panel like in Java ??
Let say if I want to create something like panel, how should I do it? Can I use group box to group everything together? I tried but it doesn't show like what panel can do. eg: can't hide every controls in that group.

Thanks. Smile | :)

FMansor

Normally if you create any window and create child windows (controls) related to it. Then you can just hide the main window and all is hidden!

Group box or normal static controls can do the job! However, if you are using the resource editor, then do the following:

in your WM_INITDIALOG try to make your group box the parent for the controls by calling SetParent. I am not sure if this will change their position, but give it a try!

I've tried to create a MainFrame app in MS VC6 by using the templates in VC6. I select creating an app using MFC with no documents, and what results is an app that only has a frame. Good! Yet when I compile the app and run it, the frame paints and dumps a deadly error from mfcocc with Abort Retry or Fail. The only option is to Abort. I have tried to look at the template for any problem, but I must admit, I'm only a novice. Any hints?

Hi!

How do you get access to the file name that you double click on, in the file explorer/ or on the desktop.
I have a custom application and a custom file extension. The application gets launched whenever I double
click on a file with that extension. However I am trying to obtain the name of the file that was double clicked.

AB