CObArray with VC.net

Hi guys,

my program meet a memory problem when I used the CObArray.
the code follows,
Class A{
...
CObArray m_ar;
}


Class A::function{
...
for(i = 0,i < size,i++)
{
m_ar.Add((CObject*)(new CRect(r)));
}
..
}
.....
A::~A()
{
for(int i = 0; i < m_ar.GetSize(); i++)
delete (CRect*)m_ar[i];

}
the code compiled and linkered in the VC 6 is ok and the program run normally...it compiled and linkered normally in VC.net but the .exe file generated by VC.net has Unhandled exception at 0x77f9180c in .exe: User breakpoint.
the breakpiont in VC.net
int __cdecl _heapchk (void)
{
...
if (!HeapValidate(_crtheap, 0, NULL))//line 104
{
if (GetLastError() == ERROR_CALL_NOT_IMPLEMENTED)
{
_doserrno = ERROR_CALL_NOT_IMPLEMENTED;
errno = ENOSYS;
}
else
retcode = _HEAPBADNODE;
}
...
}
.exe!_heapchk() Line 104 + 0x10 C
.exe!_CrtCheckMemory() Line 1500 + 0x5 C
.exe!_free_dbg_lk(void * pUserData=0x02018ab8, int nBlockUse=1) Line 1100 + 0x5 C
.exe!_free_dbg(void * pUserData=0x02018ab8, int nBlockUse=1) Line 1070 + 0xd C
.exe!operator delete(void * p=0x02018ab8) Line 365 + 0xb C++


I try the following method to solve the problem but it failed
int size = m_ar.GetSize();
if(size != 0){
CRect* pRect[10000] ;//10000 must biger than the size

for(int i = 0; i < size;i++){

pRect[i] = (CRect*)m_ar[i];

}
m_ar.RemoveAll();
for (i = 0; i < size;i++){

delete pRect[i];

}
VC.net still break in the line delete pRect[i] when i run the .exe
file

i try to only use the code m_ar.RemoveAll();it is ok...but it seems not to delete the pointer allocated by the operator new.

how could i solve the problem in VC.net?
what is the difference of CObArray between VC.net and VC6,or what is the difference of the delete between VC.net and VC6?

thanks in advance

anyone know about detecting the heap?
how can i monitor allocation of the heap?
I use class1* p = new class1; Is it allocated on the default heap or other heap?
what do the following output of CMemoryState::DumpStatistics stand for?
Memory leaked
0 bytes in 0 Free Blocks.
-626 bytes in -13 Normal Blocks.
0 bytes in 0 CRT Blocks.
0 bytes in 0 Ignore Blocks.
-1212 bytes in -6 Client Blocks.
Largest number used: 178 bytes.
Total allocations: 988 bytes.

Are all the blocks allocatec on the same heap?
what do the negative integer mean?
what does the largest mumber mean?

where can i get the article that introduce allocation on the heap?
thanks in advance