CTreeCtrl problem in MFC

nbugalia

The function ItemHasChildren (TreeItem) returns true for a perticular node but GetChildItem (TreeItem) doesnot return a valid node without expanding the node TreeItem. This expanding and shrinking is causing flicker in the tree. Could anyone provide a better solution ? The sample code is following -

    if (ItemHasChildren (TreeItem))
     {
        HTREEITEM tmpTreeItem = TreeItem;
        Expand (tmpTreeItem, TVE\_TOGGLE); //Causing flicker

        TreeItem = GetChildItem (TreeItem);
        Expand (tmpTreeItem, TVE\_TOGGLE); //Causing flicker
     }

jhwurmbach

NishantB++ wrote:

expanding and shrinking is causing flicker in the tree.

Stop the tree from redrawing while you are tampering with it. From my CTreeView I do: GetTreeCtrl().SetRedraw( FALSE); ... GetTreeCtrl().SetRedraw( TRUE);

Let's think the unthinkable, let's do the undoable, let's prepare to grapple with the ineffable itself, and see if we may not eff it after all.
Douglas Adams, "Dirk Gently's Holistic Detective Agency"

nbugalia

Thanks for your reply. I have already tried this option, and it is not working. By the way, have you seen this kind of behaviour that you have to expand the tree first to get the child node, or I am doing something wrong?

jhwurmbach

NishantB++ wrote:

expand the tree first to get the child node

I have. But then I use CWaitingTreeCtrl from Codeproject[^], and there things are much more complicated. It might really be that the item does not know that it has children and how many of them.

Let's think the unthinkable, let's do the undoable, let's prepare to grapple with the ineffable itself, and see if we may not eff it after all.
Douglas Adams, "Dirk Gently's Holistic Detective Agency"

Iain Clarke Warrior Programmer

The below code is from MSDN. While their samples can be lacking sometimes, they're not usually wrong.

if (pmyTreeCtrl->ItemHasChildren(hmyItem))
{
HTREEITEM hNextItem;
HTREEITEM hChildItem = pmyTreeCtrl->GetChildItem(hmyItem);

while (hChildItem != NULL)
{
hNextItem = pmyTreeCtrl->GetNextItem(hChildItem, TVGN_NEXT);
pmyTreeCtrl->DeleteItem(hChildItem);
hChildItem = hNextItem;
}
}

The only thing I can think of that may mess it up is if your parent item does not actually have children in it, but you've manually set its item.cChildren to I_CHILDRENCALLBACK. Can you check the return value from ItemHasChildren to make sure it's 0 or 1? Iain.