CTreeCtrl :: SortChildrenCB如何使用

Question

CMyTreeCtrl* pTreeCtrl = reinterpret_cast<CMyTreeCtrl*>( lParamData );
ASSERT( pTreeCtrl->IsKindOf( RUNTIME_CLASS( CTreeCtrl ) ) ); HTREEITEM  hItem1=(HTREEITEM )lParam1;
HTREEITEM  hItem2=(HTREEITEM )lParam2;
CString strName1=pTreeCtrl->GetItemText(hItem1);
TRACE(strName1);
CString strName2=pTreeCtrl->GetItemText(hItem2);
TRACE(strName2);
可是 strName1和strName2都没有返回值

Answer 1

你在构造树的时候有没有对每个tree item调用SetItemData函数？

Answer 2

http://search.csdn.net/Expert/topic/662/662861.xml?temp=.5025598
http://search.csdn.net/Expert/topic/1363/1363237.xml?temp=.6535608

Answer 3

有，每个树都有setItemData,但是取不到值，而且pTreeCtrl的值是对的，就是下面取得HTREEITEM的时候不对

Answer 4

http://blog.csdn.net/fzd999/archive/2004/08/20/80186.aspx

Answer 5

to kingzai(stevenzhu) :
我看过了，但是做起来还是不对！！
void CDlgDlg::SortTree(HTREEITEM hItem)
{
CTreeCtrl * ptree=&m_tree;
TVSORTCB sortpage;
sortpage.hParent=hItem;
sortpage.lpfnCompare=TreeCompareFunction;
sortpage.lParam=(LPARAM)ptree;
m_tree.SortChildrenCB(&sortpage);
}
static int CALLBACK TreeCompareFunction( LPARAM lParam1, LPARAM lParam2, LPARAM lParamData )
{
CTreeCtrl* pTree=(CTreeCtrl*)lParamData;
HTREEITEM hItem1=(HTREEITEM)lParam1;
HTREEITEM hItem2=(HTREEITEM)lParam2;
CString strName1=pTree->GetItemText((HTREEITEM)lParam1);
CString strName2=pTree->GetItemText((HTREEITEM)lParam1);
return strcmp(strName1,strName2);
// DWORD dw1=pTree->GetItemData(hItem1);
// DWORD dw2=pTree->GetItemData(hItem2);
// return dw1-dw2;
}
上面显示的strName1和strName2值为“”，而且如果使用下面的GetItemData的话就出错！

Answer 6

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_wcemfc4/html/aflrfCTreeCtrlcolcolSortChildrenCB.asp
msdn example:
// Sort the item in reverse alphabetical order.
static int CALLBACK 
MyCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
  // lParamSort contains a pointer to the tree control.
  // The lParam of an item is just its handle.
  CTreeCtrl* pmyTreeCtrl = (CTreeCtrl*) lParamSort;
  CString    strItem1 = pmyTreeCtrl->GetItemText((HTREEITEM) lParam1);
  CString    strItem2 = pmyTreeCtrl->GetItemText((HTREEITEM) lParam2);  return strcmp(strItem2, strItem1);
}  // The pointer to my tree control.
  extern CTreeCtrl* pmyTreeCtrl;
  TVSORTCB tvs;  // Sort the items in the tree control using my
  // callback procedure.
  tvs.hParent = TVI_ROOT;
  tvs.lpfnCompare = MyCompareProc;
  tvs.lParam = (LPARAM) pmyTreeCtrl;  pmyTreeCtrl->SortChildrenCB(&tvs);

Answer 7

to kingzai(stevenzhu) 
这个例子我看过的，但是为什么我写的时候不对，我感觉我写的代码跟这个一样的阿。有什么问题吗？

Answer 8

应用msdn上的这个例子，我发现strItem1和strItme2也是空字符串
执行不对，我哪个地方做的不对吗？

Answer 9

lParam1和lParam2不是treeitem,而是指向tree item data的指针,你要事先设置tree item data,然后把lParam1和lParam2转换成tree item data;
struct TREEITEMDATA
{
   CString strItemText;
}
TREEITEMDATA *pItem = new TREEITEMDATA;
pItem->strItemText = GetItemText( hItem );
SetItemData( hItem , (DWORD)pItem );.... 
static int CALLBACK MyCompareProc(LPARAM lParam1, LPARAM lParam2, LPARAM lParamSort)
{
    TREEITEMDATA *pItem1 = reinterpret_cast<TREEITEMDATA*>( lParam1 );
    TREEITEMDATA *pItem2 = reinterpret_cast<TREEITEMDATA*>( lParam2 );
if(pItem1 == NULL || pItem2 == NULL )
return 0;
         return pItem1->strItemText.Compare( pItem2->strItemtext);
}
http://community.csdn.net/Expert/topic/3581/3581655.xml?temp=.8597071