Fastest way to select qtreeview items programatically...

Dariusz

Hey

I sweat I was asking for it before but I cant find topic... in any case... is this the fastest way ?

                QItemSelection sel;        
                QVector<QItemSelection>selList(items.size());
                for (int x = 0; x < items.size(); ++x) {
                    selList[x]= QItemSelection(items[x], items[x]);
                }
                for (int x = 0; x < items.size(); ++x) {
                    sel.merge(selList[x], QItemSelectionModel::Select);
                }
                mSelectionRangeOld = selectionModel()->selection();
                if (cSel) {
                    selectionModel()->clearSelection();
                }
                if (extend) {
                    selectionModel()->select(sel, QItemSelectionModel::Select | QItemSelectionModel::Rows);
                } else {
                    selectionModel()->select(sel, QItemSelectionModel::Deselect | QItemSelectionModel::Rows);
                }

Can any part of it be done in thread? I'm worried with 20-30k rows & 10 columns could be slow... like very slow...

TIA

SGaist

Hi,

Out of curiosity, why do you need to select that much elements programmatically ?

Dariusz

@SGaist 3D app, say user selects 50k meshes, I need to reflect that in tree view :- )

Taytoo

Never tried selecting 50K items before. But if they happen in a single method call/forloop, it'll likely be much faster if you:

Stop UI updates by calling qtreeview->setUpdatesEnabled(false) at the beginning and qtreeview->setUpdatesEnabled(true) at the end.
Stop item related signals from being generated by calling qtreeview->blockSignals(true) at the beginning and qtreeview->blockSignals(false) at the end.

Once this is done, then the only cpu usage would be qtreeview model being updated and final UI update at the end.

Christian Ehrlicher

Why would someone see 50k meshes in a tree view? What should the user do with this information...