extern "C" long EXPORT __stdcall GetRootItem (long Thwnd,char *filestr) {
TVITEM tvi, *_tvi;
char *_item;
char item[256];
unsigned long pid;
HANDLE process;
long ret=(long)((CTreeCtrl*)CWnd::FromHandle((HWND)Thwnd))->GetRootItem();
if (ret) {
/*
GetWindowThreadProcessId

说明
获取与指定窗口关联在一起的一个进程和线程标识符

返回值
Long，拥有窗口的线程的标识符
参数表
参数 类型及说明
lpdwProcessId Long，指定一个变量，用于装载拥有那个窗口的一个进程的标识符
hwnd Long，指定窗口句柄
*/
GetWindowThreadProcessId((HWND)Thwnd, &pid);
//用全部权限打开进程
process=OpenProcess(PROCESS_VM_OPERATION |PROCESS_VM_READ | PROCESS_VM_WRITE |PROCESS_QUERY_INFORMATION, FALSE, pid);
//给_lvi，_item分配进程级的虚拟内存空间
_tvi=(TVITEM*)VirtualAllocEx(process, NULL, sizeof(TVITEM), MEM_COMMIT, PAGE_READWRITE);
_item=(char*)VirtualAllocEx(process, NULL, 256, MEM_COMMIT, PAGE_READWRITE);
tvi.cchTextMax=256;
tvi.hItem=(HTREEITEM)ret;
tvi.mask=TVIF_TEXT;
tvi.pszText=_item;
//把_lvi写入进程
WriteProcessMemory(process, _tvi, &tvi, sizeof(TVITEM), NULL);
//发消息得到数据
::SendMessage((HWND)Thwnd, TVM_GETITEM, 0 , (LPARAM)_tvi);
//从进程中读出数据
ReadProcessMemory(process, _item, item, 256, NULL);
//copy data
memcpy(filestr,item,256);
//free memory
VirtualFreeEx(process, _tvi, 0, MEM_RELEASE);
VirtualFreeEx(process, _item, 0, MEM_RELEASE);
}
return ret;
}

extern "C" long EXPORT __stdcall GetNextItem (HWND Thwnd,long next,char *filestr) {
TVITEM tvi, *_tvi;
char item[256];
char *_item;
unsigned long pid;
HANDLE process;
long ret=(long)((CTreeCtrl*)CWnd::FromHandle(Thwnd))->GetNextSiblingItem((HTREEITEM)next);
if (ret) {
GetWindowThreadProcessId(Thwnd, &pid);
process=OpenProcess(PROCESS_VM_OPERATION |PROCESS_VM_READ | PROCESS_VM_WRITE |PROCESS_QUERY_INFORMATION, FALSE, pid);
_tvi=(TVITEM*)VirtualAllocEx(process, NULL, sizeof(TVITEM), MEM_COMMIT, PAGE_READWRITE);
_item=(char*)VirtualAllocEx(process, NULL, 256, MEM_COMMIT, PAGE_READWRITE);
tvi.cchTextMax=256;
tvi.hItem=(HTREEITEM)ret;
tvi.mask=TVIF_TEXT;
tvi.pszText=_item;
WriteProcessMemory(process, _tvi, &tvi, sizeof(TVITEM), NULL);
::SendMessage(Thwnd, TVM_GETITEM, 0 , (LPARAM)_tvi);
ReadProcessMemory(process, _item, item, 256, NULL);
memcpy(filestr,item,256);
VirtualFreeEx(process, _tvi, 0, MEM_RELEASE);
VirtualFreeEx(process, _item, 0, MEM_RELEASE);

}
return ret;
}
以上的函数可以放到dll中在vb,vc里调用，但如果机器没装vc,在vb里调用需要MFC42D.DLL，MSVCRTD.DLL。