@arguskso said in Is it possible to notify items in the model without signals?: when new data is coming I can emmit signal with an id and all delegates will receive it and one with the corresponding id will send one more signal back to the model with it's index in the model. Delegates are used for displaying, they don't know anything about the internal data structure and don't have really access to anything else except it's own index. This can't work. You have to do it the way @JonB suggested to you.

You can check you model implementation with the QAbstractItemModelTester. See this wiki entry.

Hmmmmmmmm Ok. Time to rethink my live decisions :- ) Thanks so much for info & putting up with my whining. Thanks every one! :- ) Regards Dariusz

@Dariusz said in Multithreading conversion of QModelIdnexList to treeItem crash: Well I have 100k items +/- to deal with Then you should avoid to dereference the pointers to not copy the data around. I created the base vectors via QVector<myTreeNode> vec(vecSize) and I access them all via [], so no thread should step over another thread, It does as your backtrace shows. Since you're using QVector which is implicit shared every write access to the container checks if the container needs to get detached. Maybe try with a non-implicit shared container instead (e.g. a std::vector) See http://doc.qt.io/qt-5/implicit-sharing.html for details.

@VRonin Thank you. Yesterday, I tried same things. But it was not working than later on I found, I forget to add file name in SOURCE , HEADER. Now it is work as expectation.

Then you have to propagate the information when your underlying data changes.

@mrjj yes, thank you!

@Guy-Gizmo said: The whole point of me setting it up that way is that the actual logical structure of the data and the physical arrangement and implementation of it are conceptually completely separate. The latter is abstracted away by the interface of the former. Then I think the cleanest solution is to have a tree (or w/e) that represents your logical structure, and that will abstract the whole physical layer. For a simple example you can look at the docs - the simple tree model. You can put anything in that tree and it's basically your "data interface". It also shouldn't care that the physical nodes are destroyed as long as there's a logical node living. This way you don't have with model indexes and things getting destroyed in the background, because it's the middleman's responsibility. You should hover take care to notify the model when a node/leaf from the "logical structure" tree is destroyed (through the appropriate signals), so views can make proper adjustments. I hope that helps somewhat. Kind regards.

@Trilec said: QStandardItemModel model = static_cast<QStandardItemModel>(ui->tree_shot->model()); Instance of which class is ui->tree_shot->model()? The fact that you cast it to QStandardItemModel does not make it one. If it is not QStandardItemModel or derived class you are in undefined behavior area. You should not use static_cast for any of QObject derived class anyway. Use qobject_cast and check that value is not nullptr. If you are creating model yourself is ui->tree_shot a QTreeWidget? If it is custom model you probably did not call proper functions when changing the model. In this case widget will not be updated properly.

Cool, Thanks for all the insite: I have solved the problem with a little more testing. For the sake of completeness and for others Ive included my code: void DialogStructureXML::on_btn_add_toroot_released() { QModelIndex currentIndex = ui->tree->selectionModel()->currentIndex(); QModelIndex rootIndex = ui->tree->rootIndex(); QModelIndex traceIndex = currentIndex; QModelIndex child = currentIndex; tree_model *model = (tree_model*) ui->tree->model(); int rowCount = model->rowCount(); int currentRow = 0; int prevRow = 0; //some string cleanup QString ItemText = ui->edit_textvaluefortree->text() ; ItemText.simplified(); //If its a valid index (ie: valid something in the GUI tree) trace back to the parent if ( traceIndex.isValid() ) { while ( traceIndex.isValid() ) { currentRow = traceIndex.row()+1; traceIndex = model->parent(traceIndex); } } if (!model->insertRow(currentRow, rootIndex)) return; child = model->index(currentRow, 0, rootIndex); //Column index 0 model->setData(child, QVariant( ItemText ), Qt::EditRole); return; }

The dummy child is the culprit. It did not set the parent so the parent is invalid.

Thank you. It worked!

Hi and welcome to devnet, What about painting a partially transparent rectangle over the part of the text that should be highlighted ? You could draw the text first and then the rectangle over. Hope it helps

@StephanB hi and welcome The thread is 4 years old so the persons are most likely never to see it. The rest of the code belong to a custom/subclass model. So what call the code, it the framework / the view that use this model. You can read about it here: http://doc.qt.io/qt-5/model-view-programming.html https://www.youtube.com/watch?v=ytKDsJgJa4k http://www.informit.com/articles/article.aspx?p=1405547&seqNum=3