How to accelerate the selection in the QTableView ?

[cyberpunker]

I use the MVC to show a bund of of filenames , and there are opertions of selecting all and dissecting all in the CTableView . The number of files may thousands , so , I write a thread to do these ,like:

for (int row = 0; row < m_ImgMgr->m_TableModel->rowCount(); row++)
	{


		//QtSleep(5);

		for (int column = 0; column < m_ImgMgr->m_TableModel->columnCount(); column++)
		{

			//LogLog( QString(" sel 1") ) ;
			m_ImgMgr->listImages2->selectionModel()->select(m_ImgMgr->listImages2->model()->index(row, column), QItemSelectionModel::Select);

		}

		//LogLog(QString(" sel 2"));

		m_ImgMgr->labelImageIndex->setText(QString::number(row+1) + QString("/") + QString::number(m_ImgMgr->m_TableModel->rowCount()));
		
		//LogLog(QString(" sel 3"));

	}

but consuming time is not acceptable . And if the number is very large , the operation seems become more and more slowly by the end of the loop , it can be seen by the count number displayed in the GUI .

I also tried like below:

	QItemSelection sel = m_ImgMgr->listImages2->selectionModel()->selection( ) ;

	QModelIndex topleft     = m_ImgMgr->listImages2->model()->index( 0 , 0 ) ;
	QModelIndex bottonright = m_ImgMgr->listImages2->model()->index(m_ImgMgr->m_TableModel->rowCount(), 3 ) ;

	sel.select( topleft  , bottonright ) ;

no funtional.

[VRonin]

I can't reproduce the problem. try this minimal example and see if it works for you:

#include <QTableView>
#include <QVBoxLayout>
#include <QStandardItemModel>
#include <QApplication>
#include <QPushButton>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QWidget mainWid;
    QAbstractItemModel* model = new QStandardItemModel(&mainWid);
    model->insertColumns(0,4);
    model->insertRows(0,5000);
    for(int rowIter = 0, maxRow = model->rowCount();rowIter<maxRow;++rowIter){
        for(int colIter = 0, maxCol = model->columnCount();colIter<maxCol;++colIter){
            model->setData(model->index(rowIter,colIter),QStringLiteral("%1,%2").arg(rowIter+1).arg(colIter+1));
        }
    }
    QTableView* table = new QTableView(&mainWid);
    table->setModel(model);
    QPushButton* selectAllButton = new QPushButton(QStringLiteral("Select All"),&mainWid);
    QObject::connect(selectAllButton,&QPushButton::clicked,table,[table]()->void{
        const QItemSelection selec(table->model()->index(0,0),table->model()->index(table->model()->rowCount()-1,table->model()->columnCount()-1));
        table->selectionModel()->select(selec,QItemSelectionModel::ClearAndSelect);
    });
    QVBoxLayout* mainLay = new QVBoxLayout(&mainWid);
    mainLay->addWidget(selectAllButton);
    mainLay->addWidget(table);
    mainWid.show();
    return a.exec();
}

P.S.

I write a thread to do these

Don't do GUI operations in secondary threads

[Christian Ehrlicher]

How should your second approach work when you don't pass it to the selection model?
And doing stuff for a model/view in a thread will not work out of the box since the models and views are not threadsafe

[cyberpunker]

@VRonin said in How to accelerate the selection in the QTableView ?:

QTableView* table = new QTableView(&mainWid);

So great , I am still totally ignorant to MVC .

Really apreciation.

[cyberpunker]

@Christian-Ehrlicher

thanks for your suggestion.