@VRonin
Ho provato l'esempio della libreria sqlwidgetmapper ed ho constatato che avviene la stessa cosa. Per semplicità ti allego i sorgenti ai quali ho aggiunto qualche campo in più per rendere più evidente il problema:
sqlwidgettmapper.pro
HEADERS = window.h
SOURCES = main.cpp \
window.cpp
QT += sql widgets
# install
target.path = $$[QT_INSTALL_EXAMPLES]/sql/sqlwidgetmapper
INSTALLS += target
window.h
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef WINDOW_H
#define WINDOW_H
#include <QWidget>
QT_BEGIN_NAMESPACE
class QComboBox;
class QDataWidgetMapper;
class QItemSelectionModel;
class QLabel;
class QLineEdit;
class QPushButton;
class QSqlRelationalTableModel;
class QStandardItemModel;
class QStringListModel;
class QTextEdit;
QT_END_NAMESPACE
//! [Window definition]
class Window : public QWidget
{
Q_OBJECT
public:
Window(QWidget *parent = nullptr);
private slots:
void updateButtons(int row);
void saveBtn(void); //^^^
private:
void setupModel();
QLabel *nameLabel;
QLabel *addressLabel;
QLabel *typeLabel;
QLineEdit *nameEdit;
QTextEdit *addressEdit;
QComboBox *typeComboBox;
QPushButton *nextButton;
QPushButton *previousButton;
QPushButton *saveButton; //^^^
QSqlRelationalTableModel *model;
QItemSelectionModel *selectionModel;
QDataWidgetMapper *mapper;
int typeIndex;
};
//! [Window definition]
#endif
window.cpp
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
//Cerca ^^^ per eliminare le mie modifiche
#include <QtWidgets>
#include <QtSql>
#include "window.h"
//! [Set up widgets]
Window::Window(QWidget *parent)
: QWidget(parent)
{
setupModel();
nameLabel = new QLabel(tr("Na&me:"));
nameEdit = new QLineEdit();
addressLabel = new QLabel(tr("&Address:"));
addressEdit = new QTextEdit();
typeLabel = new QLabel(tr("&Type:"));
typeComboBox = new QComboBox();
nextButton = new QPushButton(tr("&Next"));
previousButton = new QPushButton(tr("&Previous"));
saveButton = new QPushButton(tr("Salva")); //^^^
nameLabel->setBuddy(nameEdit);
addressLabel->setBuddy(addressEdit);
typeLabel->setBuddy(typeComboBox);
//! [Set up widgets]
//! [Set up the mapper]
QSqlTableModel *relModel = model->relationModel(typeIndex);
typeComboBox->setModel(relModel);
typeComboBox->setModelColumn(relModel->fieldIndex("description"));
mapper = new QDataWidgetMapper(this);
mapper->setModel(model);
mapper->setItemDelegate(new QSqlRelationalDelegate(this));
mapper->addMapping(nameEdit, model->fieldIndex("name"));
mapper->addMapping(addressEdit, model->fieldIndex("address"));
mapper->addMapping(typeComboBox, typeIndex);
//! [Set up the mapper]
//! [Set up connections and layouts]
connect(previousButton, &QPushButton::clicked,
mapper, &QDataWidgetMapper::toPrevious);
connect(nextButton, &QPushButton::clicked,
mapper, &QDataWidgetMapper::toNext);
connect(mapper, &QDataWidgetMapper::currentIndexChanged,
this, &Window::updateButtons);
connect(saveButton, &QPushButton::clicked,
this, &Window::saveBtn); //^^^
QGridLayout *layout = new QGridLayout();
layout->addWidget(nameLabel, 0, 0, 1, 1);
layout->addWidget(nameEdit, 0, 1, 1, 1);
layout->addWidget(previousButton, 0, 2, 1, 1);
layout->addWidget(addressLabel, 1, 0, 1, 1);
layout->addWidget(addressEdit, 1, 1, 2, 1);
layout->addWidget(nextButton, 1, 2, 1, 1);
layout->addWidget(typeLabel, 3, 0, 1, 1);
layout->addWidget(typeComboBox, 3, 1, 1, 1);
layout->addWidget(saveButton, 2, 2, 1, 1); //^^^
setLayout(layout);
setWindowTitle(tr("SQL Widget Mapper"));
mapper->toFirst();
}
//! [Set up connections and layouts]
//! [Set up the main table]
void Window::setupModel()
{
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName(":memory:");
if (!db.open()) {
QMessageBox::critical(0, tr("Cannot open database"),
tr("Unable to establish a database connection.\n"
"This example needs SQLite support. Please read "
"the Qt SQL driver documentation for information how "
"to build it."), QMessageBox::Cancel);
return;
}
QSqlQuery query;
query.exec("create table person (id int primary key, "
"name varchar(20), address varchar(200), typeid int)");
query.exec("insert into person values(1, 'Alice', "
"'<qt>123 Main Street<br/>Market Town</qt>', 101)");
query.exec("insert into person values(2, 'Bob', "
"'<qt>PO Box 32<br/>Mail Handling Service"
"<br/>Service City</qt>', 102)");
query.exec("insert into person values(3, 'Carol', "
"'<qt>The Lighthouse<br/>Remote Island</qt>', 103)");
query.exec("insert into person values(4, 'Donald', "
"'<qt>47338 Park Avenue<br/>Big City</qt>', 101)");
query.exec("insert into person values(5, 'Emma', "
"'<qt>Research Station<br/>Base Camp<br/>"
"Big Mountain</qt>', 103)");
//! [Set up the main table]
//! [Set up the address type table]
query.exec("create table addresstype (id int, description varchar(20))");
query.exec("insert into addresstype values(101, 'Home')");
query.exec("insert into addresstype values(102, 'Work')");
query.exec("insert into addresstype values(103, 'Other')");
//CAMPI AGGIUNTI -------------------------------------------
query.exec("insert into addresstype values(104, 'Casa')");
query.exec("insert into addresstype values(105, 'Lavoro')");
query.exec("insert into addresstype values(106, 'Altro')");
//---------------------------------------------------------
model = new QSqlRelationalTableModel(this);
model->setTable("person");
model->setEditStrategy(QSqlTableModel::OnManualSubmit);
typeIndex = model->fieldIndex("typeid");
model->setRelation(typeIndex,
QSqlRelation("addresstype", "id", "description"));
model->select();
}
//! [Set up the address type table]
//! [Slot for updating the buttons]
void Window::updateButtons(int row)
{
previousButton->setEnabled(row > 0);
nextButton->setEnabled(row < model->rowCount() - 1);
}
//! [Slot for updating the buttons]
//^^^
void Window::saveBtn(void)
{
model->submitAll();
}
//^^^
main.cpp
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, you may use this file under the terms of the BSD license
** as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QApplication>
#include "window.h"
int main(int argc, char **argv)
{
QApplication app(argc, argv);
Window window;
window.show();
return app.exec();
}
Questo è quanto accade:
sqlwdmp_1.jpeg
Modifico il type da inglese ad italiano:
sqlwdmp_2.jpeg
sqlwdmp_3.jpeg
Ora premo NEXT per passare al nome successivo:
sqlwdmp_4.jpeg
e poi torno indietro con PREVIUS:
sqlwdmp_5.jpeg
e la combo NON viene aggiornata al tipo che avevo scelto, ma mantiene quello dell'ultimo nome visualizzato fino a che non salvo nel database con SALVA.
Ciao
Giovanni
