Tree Item Selection States

I have a tree control in one of my document views and I need to be able to enable/disable selection of items in the tree.  This means that when an item is selected and dragged to my other view, I want to still show it in the tree, but disable it from being selected and dragged again.  Any suggestions??
keithddAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

rob_garnerCommented:
In the documentation there is a state described - TVIS_DISABLED. Unfortunately this state does not really exist.

So try this...

First, after processing the initial drag set the item so that you know it has been dragged.
You could either do something like...

a.      SetItemState(hItem, TVIS_CUT, TVIS_CUT);
      This will give a visual cue that the item is not available.

      - or -

b.      Set some flag in LPARAM that you can later query
(next steps assume use of TVIS_CUT)

Next, process the TVN_BEGINDRAG notification something like this...

      UINT nFlags = GetItemState(hItem, TVIS_CUT);
      if ( nFlags & TVIS_CUT )
      {
            *pResult = 1;
            AfxMessageBox("Can't drag");
            return;
      }

This will prevent the item from being dragged, but will still allow the item to be selected.

To prevent the selection process the TVN_SELCHANGING notification something like this

void CDiskTreeCtrl::OnSelchanging(NMHDR* pNMHDR, LRESULT* pResult)
{
      NM_TREEVIEW* pNMTreeView = (NM_TREEVIEW*)pNMHDR;

      HTREEITEM hItem = pNMTreeView->itemNew.hItem;
      UINT nFlags = GetItemState(hItem, TVIS_CUT);
      if ( nFlags & TVIS_CUT )
      {
            *pResult = 1;
            return;
      }
      
      *pResult = 0;
}


0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
System Programming

From novice to tech pro — start learning today.