Get the Contents of a QComboBox

Question

I need to get an QStringList or an array containing all QStrings in a QComboBox.

I can't find a QComboBox method that does this, in fact I can't even find a QAbstractItemModel method that does this.

Is this really my only option:

std::vector< QString > list( myQComboBox.count() );

for( auto i = 0; i < list.size(); i++ )
{
    list[i] = myQComboBox.itemText( i );
}

There is no such function, AFAK. Why don't you like the approach you use (iteration over all items in the combo box)? — vahancho, Sep 18 '14 at 12:25
@vahancho I presume it to be quite wasteful, especially as the size of the `QComboBox` grows. — Jonathan Mee, Sep 18 '14 at 12:28
But maybe storing the content of the combo box into another container is also wasteful? Why do you need that? This can explain, why there is no such function in the API. — vahancho, Sep 18 '14 at 12:39
What does the container of values get you that the member function `QComboBox::itemText` cannot? — rubenvb, Sep 18 '14 at 12:54
I am going to clear `myQComboBox` and repopulate it, I need to identify elements that have changed. — Jonathan Mee, Sep 18 '14 at 13:14

DowntownDev · Answer 1 · 2017-07-25T06:41:44.377

13

Your answer looks fine, but you could also use a QStringList instead of a vector.

QStringList itemsInComboBox; 
for (int index = 0; index < ui->combo_box->count(); index++)
    itemsInComboBox << ui->combo_box->itemText(index);

edited Jul 25 '17 at 06:41

answered Dec 12 '16 at 06:12

DowntownDev

842
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score 9 · Accepted Answer · answered Sep 18 '14 at 13:18

QAbstractItemModel can contain images, trees other kinds of data that can be kept in QVariant. That is why you can't get a QStringList from it. It is pointless.

However, there is a class QStringListModel inherited from QAbstractItemModel that is intended to keep strings. And as you can expect it has method stringList().

QComboBox allows you to change a default model which it uses to another one. By default it uses QStandardItemModel. Change it to a string list model after creating the combo box.

 QStringListModel* cbModel = new QStringListModel();
 comboBox->setModel(cbModel);

Now you can get what you want:

QStringList list = cbModel->stringList();

This is not the solution I'd hoped for but it does legitimately solve the problem. — Jonathan Mee, Sep 19 '14 at 11:09

Dmitry Sazonov · Answer 3 · 2014-09-18T14:17:23.623

2

Don't do a premature optimization. Your code is ok. You may use qobject_cast<QStandardItemModel*>(combo.model()); to get extended access to combobox data.

Also, you can implement your own QAbstractItemModel which will store data as QStringList, and provide access to it.

edited Sep 18 '14 at 14:17

answered Sep 18 '14 at 12:40

Dmitry Sazonov

8,801
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Get the Contents of a QComboBox

3 Answers3