QTableView and how to set first row to be always the default selected

[cpuinthebrain]

Hi,

I have a QWidget with QTableView.The program is written on way that if no row is selected the program crushes.
Because of this i want that the first row to be always selected as default.
Any suggestions?

[Ashkan_s]

You can set a row as selected using QTableView::selectRow().

[cpuinthebrain]

Strangely but it was the first thing i have tried.Unfortunately giving a parameter 1 for instance nothing happens.No row is selected.

[cpuinthebrain]

I'm wandering that nobody know why this doesn't select any row:

ui->tableView_clients->setSelectionMode(QAbstractItemView::SingleSelection);
ui->tableView_clients->selectRow(1);

ui->tableView_clients->setSelectionMode(QAbstractItemView::SingleSelection);
ui->tableView_clients->selectRow(1);

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HELP PLEASE

[huilui]

Hm, maybe you also need to define a selection behaviour (QAbstractItemView::setSelectionBehavior), in particular QAbstractItemView::SelectRows. I think the default is QAbstractItemView::SelectItems, and that in combination with QAbstractItemView::SingleSelection could pose a problem when trying to select a row with more than one column.

Also note, that the first row has index 0 and not 1

[cpuinthebrain]

Thanks for the replay, but as default in the .ui file is set on selectionBehavior - SelectRows.Due to the 1 i know very well that everything in the programming start from 0, i just set to 1.
When opens nothing is selected.

[ChrisW67]

This small, self-contained example demonstrates that it does work:

#include <QtGui>
#include <QDebug>
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
 
    QStandardItemModel model(4, 4);
    for (int row = 0; row < 4; ++row) {
        for (int column = 0; column < 4; ++column) {
            QStandardItem *item = new QStandardItem(QString("row %0, column %1").arg(row).arg(column));
            model.setItem(row, column, item);
        }
    }
 
    QTableView v;
    v.setModel(&model);
    v.setSelectionMode(QAbstractItemView::SingleSelection);                                                   
    v.setSelectionBehavior(QAbstractItemView::SelectRows);                                                    
    v.selectRow(0);                                                                                           
    v.show();                                                                                                 
 
    return app.exec();                                                                                        
}

#include <QtGui>
#include <QDebug>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QStandardItemModel model(4, 4);
    for (int row = 0; row < 4; ++row) {
        for (int column = 0; column < 4; ++column) {
            QStandardItem *item = new QStandardItem(QString("row %0, column %1").arg(row).arg(column));
            model.setItem(row, column, item);
        }
    }

    QTableView v;
    v.setModel(&model);
    v.setSelectionMode(QAbstractItemView::SingleSelection);                                                   
    v.setSelectionBehavior(QAbstractItemView::SelectRows);                                                    
    v.selectRow(0);                                                                                           
    v.show();                                                                                                 
                                                                                                              
    return app.exec();                                                                                        
}

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If you select row 1 and there is only one row in the table, row 0, then of course nothing is selected. We are not privy to the data your model is producing or any of the other things your code might be doing to the model or view, so we cannot tell you how to fix your code.

The program is written on way that if no row is selected the program crushes. ... Any suggestions?

This is the problem. Fix the program so that if there is no selected row in the table the user cannot trigger the event that would cause the program to "crush". Or, if you cannot stop the user triggering such events, make the offending code check for a selection and do nothing if one is not found (this is good defensive programming anyway). The alternative is to find everywhere a selection could be lost, for example deleting a row or resetting the model, and making sure you select something.