Problem with ListView API : LVM_ISERTITEM

[ravjak]

"Hi I'm developing dll which will do some changing stuff with ListView. I have a funny problem I want to change value of iImage in a LV_ITEM according to pszText value. Problem occurs when I want to test value of pszText, exception ouccrs Access Violation 0xC0000005 :(. But I'm testing if pitem and pitem->pszText are not null even if I tryed to use strdup(pitem->pszText) the same exception occurs. There is no problem when I tryed to change value of iItem. Is is somehow connected witch injection dll into some application ?? and its address space ?? " (WNDPROC) gfnListProc; //in some previous called function gfnListProc = (WNDPROC)SetWindowLong(listview, GWL_WNDPROC,(LONG)ListProc); __declspec(dllexport) LRESULT CALLBACK ListProc(HWND hwnd, UINT uiMsg,WPARAM wParam, LPARAM lParam) { switch (uiMsg) { case LVM_INSERTITEM: { LV_ITEM FAR* pitem = (LV_ITEM FAR*) lParam; if(pitem && pitem->pszText) MessageBox(0, pitem->pszText,":-)",MB_OK); break; } } return CallWindowProc(gfnListProc, hwnd, uiMsg, wParam, lParam); } //from commctr.h typedef struct tagLVITEMW { UINT mask; int iItem; int iSubItem; UINT state; UINT stateMask; LPWSTR pszText; int cchTextMax; int iImage; LPARAM lParam; #if (_WIN32_IE >= 0x0300) int iIndent; #endif } LVITEMW, FAR* LPLVITEMW; #define ListView_InsertItem(hwnd, pitem) \ (int)SNDMSG((hwnd), LVM_INSERTITEM, 0, (LPARAM)(const LV_ITEM FAR*)(pitem)) Thaks for reading that stuff :-) Pain is a weakness living the body

[Andrew Quinn AUS]

Hi, Are you sure that lParam is pointing to a valid LV_ITEM structure? Cheers, Andy

[ravjak]

I'm pretty sure because listview is a HWND of list control and its valid Pain is a weakness living the body

[bikram singh]

Check that mask member contains LVIF_TEXT This flag indicates that the pszText member contains a valid address. If the flag is not set, the member could contain any "address". Also, check that cchTextMax member is not zero. (not really required) Bikram Singh

[ravjak]

this pice of code doesn't work :( case LVM_INSERTITEM: { LV_ITEM FAR* pitem = (LV_ITEM FAR*) lParam; if(!pitem && !pitem->pszText) break; if( pitem->mask & LVIF_TEXT == LVIF_TEXT && pitem->cchTextMax>0) { MessageBox(okno,pitem->pszText,":-)",MB_OK); } break; any other ideas :confused: :mad::mad: Pain is a weakness living the body

[bikram singh]

Try using brackets to delimit each expression you are testing in the if statement. Bikram Singh

[jmkhael]

What happens if pitem != NULL and pitem->pszText = NULL? (Hint: It wont break) I would do the test: if(pitem && pitem->pszText) { // Do the dance... } Papa while (TRUE) Papa.WillLove ( Bebe ) ;

[ravjak]

Not working hmmm hardcore hehe. Im testing changing iImage value according to iItem and it seems to be good if I know sequence of adding apriori, which will require some more coding. Anyway its really strage stuff isn't it :confused: Pain is a weakness living the body

[jmkhael]

Try this case LVM_INSERTITEM: { LPLVITEM pitem = (LPLVITEM) lParam; if(pitem && pitem->pszText) { if( ((pitem->mask & LVIF_TEXT) == LVIF_TEXT)) { MessageBox(okno,pitem->pszText,"",MB_OK); } } break; Papa while (TRUE) Papa.WillLove ( Bebe ) ;

[ravjak]

Not working. Plese remind me next time do not take a project for windows. Pain is a weakness living the body

[ravjak]

But I thing I know why is it so. According to spy ++ this is a ATL:SysTreeView control. Maybe as a lparam they are sending some other struct than LV_ITEM:confused: Pain is a weakness living the body

[jmkhael]

Where is it crashing? Papa while (TRUE) Papa.WillLove ( Bebe ) ;

[bikram singh]

I would do: if(pitem) { if(pitem->pszText) { // Do the dance... } } Bikram Singh

[ravjak]

Im hooking into OE and it crashes when OE adds new items to address list. when i use olny iImage eg iImage = 2 it works properly but i want test pszText vaule and according to this set proper valus of iImage :) Pain is a weakness living the body

[ravjak]

not working too i think this not valid pointer beacuse its not the same address space I had the similar problem some time ago when i wannted to send some char * as wparam or lparam using SendMessage. I had to use WM_COPYDATA then char * goes thru kernel memory and pointer is valid:confused: Pain is a weakness living the body