C / C++ / MFC

<br />
// Gain a pointer to our tree control<br />
<br />
CTreeCtrl* pCtrl = (CTreeCtrl*) GetDlgItem(IDC_TREE1);<br />
ASSERT(pCtrl != NULL);<br />
<br />
// Insert a root item using the structure. We must<br />
// initialize a TVINSERTSTRUCT structure and pass its<br />
// address to the call. <br />
<br />
TVINSERTSTRUCT tvInsert;<br />
tvInsert.hParent = NULL;<br />
tvInsert.hInsertAfter = NULL;<br />
tvInsert.item.mask = TVIF_TEXT;<br />
tvInsert.item.pszText = _T("United States");<br />
<br />
HTREEITEM hCountry = pCtrl->InsertItem(&tvInsert);<br />
<br />
// Insert subitems of that root. Pennsylvania is<br />
// a state in the United States, so its item will be a child<br />
// of the United States item. We won't set any image or states,<br />
// so we supply only the TVIF_TEXT mask flag. This<br />
// override provides nearly complete control over the<br />
// insertion operation without the tedium of initializing<br />
// a structure. If you're going to add lots of items<br />
// to a tree, you might prefer the structure override<br />
// as it affords you a performance win by allowing you<br />
// to initialize some fields of the structure only once,<br />
// outside of your insertion loop.<br />
<br />
HTREEITEM hPA = pCtrl->InsertItem(TVIF_TEXT,<br />
   _T("Pennsylvania"), 0, 0, 0, 0, 0, hCountry, NULL);<br />
<br />
// Insert the "Washington" item and assure that it is<br />
// inserted after the "Pennsylvania" item. This override is <br />
// more appropriate for conveniently inserting items with <br />
// images.<br />
<br />
HTREEITEM hWA = pCtrl->InsertItem(_T("Washington"),<br />
   0, 0, hCountry, hPA);<br />
<br />
// We'll add some cities under each of the states.<br />
// The override used here is most appropriate<br />
// for inserting text-only items.<br />
<br />
pCtrl->InsertItem(_T("Pittsburgh"), hPA, TVI_SORT);<br />
pCtrl->InsertItem(_T("Harrisburg"), hPA, TVI_SORT);<br />
pCtrl->InsertItem(_T("Altoona"), hPA, TVI_SORT);<br />
<br />
pCtrl->InsertItem(_T("Seattle"), hWA, TVI_SORT);<br />
pCtrl->InsertItem(_T("Kalaloch"), hWA, TVI_SORT);<br />
pCtrl->InsertItem(_T("Yakima"), hWA, TVI_SORT);