How to differentiate some LVITEMS (file or directory)?

Question

So I am implementing a CListCtrl using PostMessage(LVN_INSERTITEM,0,(LPARAM) lvitem). And I need a way to differentiate lvitems, so that later on when I will get a lvitem, to tell if it's a file or directory. I need to implement using PostMessage, so I don't know exactly when the item is inserted. I am allocating the item dynamically (storing the dynamically allocated memory pointer in the lParam attribute of the LVITEM structure, so after it is inserted I treat it's notification and deallocate the memory getting the address from the item).

Answer 1

You can use the lParam member of the LVITEM structure to set custom data for you list item:

// custom structure to hold some information
struct listItem {
   int value;
   char path[MAX_PATH];
};

// initialize a custom object to hold a value and a path
LVITEM lvi;
listItem* pItem = new listItem();
pItem->value = 666;
sprintf(pItem->path,"c:\\\\xampp\\htdocs");

// initialize a LVITEM object
memset(&lvi, 0, sizeof(lvi)),
lvi.pszText = "My Folder";
lvi.mask = LVIF_PARAM | LVIF_TEXT;
// lParam points to our custom object
lvi.lParam = (LPARAM)pItem;
SendMessage(g_hwndLV, LVM_INSERTITEM, 0, (LPARAM)&lvi);

Note: In this case you should free the memory pointed to by lParam using delete.

Answer 2

You can set arbitrary data with CListCtrl::SetItemData, but you should use the method CListCtrl::InsertItem instead of using PostMessage (which is a low-level Win32 call, not MFC).