QDateEdit et QString

merci Francis, j'ai vraiment besoin d'aide pour mon projet!
voila le code de la page cpp:

#include <QtGui>
#include "addressbook.h"
#include <QSqlQuery>
#include <QFont>
#include <QDateEdit>
#include <QComboBox>


AddressBook::AddressBook(QWidget *parent)
: QWidget(parent)
{
//QPixmap *img=new QPixmap;
//const QString filename="C:\Users\Public\Pictures\Sample Pictures\Toucan.jpeg";
//img->load(filename);

QLabel *nameLabel = new QLabel(tr("Nom:"));
nameLine = new QLineEdit;
nameLine->setReadOnly(true);
nameLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *prenomLabel = new QLabel(tr("Prénom:"));
prenomLine = new QLineEdit;
prenomLine->setReadOnly(true);
prenomLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *addressLabel = new QLabel(tr("Adresse:"));
addressText = new QTextEdit;
addressText->setMaximumSize(QSize(135, 60));
addressText->setReadOnly(true);
addressText->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *villeLabel = new QLabel(tr("Ville:"));
villeLine = new QLineEdit;
villeLine->setReadOnly(true);
villeLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *telLabel = new QLabel(tr("Tel:"));
telLine = new QLineEdit;
telLine->setReadOnly(true);
telLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *faxLabel = new QLabel(tr("Fax:"));
faxLine = new QLineEdit;
faxLine->setReadOnly(true);
faxLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *mailLabel = new QLabel(tr("Mail:"));
mailLine = new QLineEdit;
mailLine->setReadOnly(true);
mailLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *descriptionContratLabel = new QLabel(tr("Description du contrat:"));
descriptionContratText = new QTextEdit;
descriptionContratText->setMaximumSize(QSize(135, 60));
descriptionContratText->setReadOnly(true);
descriptionContratText->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *dateLabel = new QLabel(tr("Date:"));

QLabel *typeClientLabel = new QLabel(tr("Type du client:"));


QLabel *montantLabel = new QLabel(tr("Montant:"));
montantLine = new QLineEdit;
montantLine->setReadOnly(true);
montantLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

//QLabel *typeClientLabel = new QLabel(tr("Type de client:"));
//typeClientLine = new QLineEdit;
//typeClientLine->setReadOnly(true);
//typeClientLine->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QLabel *premierLabel = new QLabel(tr("Veuillez remplir les champs concernant le contrat"));
premierLabel->setFont(QFont("Comic Sans MS", 8, QFont::Bold, true));

QLabel *deuxiemeLabel = new QLabel(tr("Veuillez remplir les champs concernant le client"));
deuxiemeLabel->setFont(QFont("Comic Sans MS", 8, QFont::Bold, true));

QDateEdit *date = new QDateEdit();
date->setObjectName(QString::fromUtf8("date"));
date->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

QComboBox *typeClient = new QComboBox();
typeClient->setObjectName(QString::fromUtf8("comboBox"));
typeClient->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
typeClient->insertItems(0, QStringList()
<< QApplication::translate("Form", "Client fid\303\250le", 0, QApplication::UnicodeUTF8)
<< QApplication::translate("Form", "Client litigieux", 0, QApplication::UnicodeUTF8)
);


ajouterButton = new QPushButton(tr("&Ajouter"));
ajouterButton->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
//btnAjouterContrat=new QPushButton(tr("Ajouter Contrat"));

//! [instantiating findButton]

//! [instantiating findButton]
enregistrerButton = new QPushButton(tr("&Enregistrer"));
enregistrerButton->hide();
annulerButton = new QPushButton(tr("&Annuler"));
annulerButton->hide();



//! [instantiating FindDialog]

//! [instantiating FindDialog]

connect(ajouterButton, SIGNAL(clicked()), this, SLOT(ajouterContact()));
//connect(btnAjouterContrat, SIGNAL(clicked()), this, SLOT(AjouterContrat()));
connect(enregistrerButton, SIGNAL(clicked()), this, SLOT(enregistrerContact()));

connect(annulerButton, SIGNAL(clicked()), this, SLOT(annuler()));

//! [signals and slots for find]
//connect(chercherButton, SIGNAL(clicked()), this, SLOT(chercherContact()));
//! [signals and slots for find]

QVBoxLayout *buttonLayout1 = new QVBoxLayout;

buttonLayout1->addWidget(ajouterButton);
//! [adding findButton to layout]

//! [adding findButton to layout]
buttonLayout1->addWidget(enregistrerButton);
buttonLayout1->addWidget(annulerButton);
buttonLayout1->addStretch();



QGridLayout *mainLayout = new QGridLayout;
mainLayout->addWidget(deuxiemeLabel, 0, 0);
mainLayout->addWidget(nameLabel, 1, 0);
mainLayout->addWidget(nameLine, 1, 1);
mainLayout->addWidget(prenomLabel, 2, 0);
mainLayout->addWidget(prenomLine, 2, 1);
mainLayout->addWidget(addressLabel, 7, 0, Qt::AlignTop);
mainLayout->addWidget(addressText, 7, 1);
mainLayout->addWidget(villeLabel, 4, 0);
mainLayout->addWidget(villeLine, 4, 1);
mainLayout->addWidget(telLabel, 5, 0);
mainLayout->addWidget(telLine, 5, 1);
mainLayout->addWidget(faxLabel, 6, 0);
mainLayout->addWidget(faxLine, 6, 1);
mainLayout->addWidget(mailLabel, 3, 0);
mainLayout->addWidget(mailLine, 3, 1);
mainLayout->addWidget(premierLabel, 0, 2);
mainLayout->addWidget(dateLabel, 1, 2);
mainLayout->addWidget(date, 1, 3);
mainLayout->addWidget(descriptionContratLabel, 4, 2, Qt::AlignTop);
mainLayout->addWidget(descriptionContratText, 4, 3);
mainLayout->addWidget(montantLabel, 2, 2);
mainLayout->addWidget(montantLine, 2, 3);
mainLayout->addWidget(typeClientLabel, 3, 2);
mainLayout->addWidget(typeClient, 3, 3);
mainLayout->addLayout(buttonLayout1, 1, 4);

setLayout(mainLayout);
setWindowTitle(tr("Ajouter client"));
}

void AddressBook::ajouterContact()
{
oldName = nameLine->text();
oldPrenom = prenomLine->text();
oldAddress = addressText->toPlainText();
oldVille = villeLine->text();
oldTel = telLine->text();
oldFax = faxLine->text();
oldMail = mailLine->text();
oldDescriptionContrat = descriptionContratText->toPlainText();
//oldDateContrat = dateLine->text();


nameLine->clear();
prenomLine->clear();
addressText->clear();
villeLine->clear();
telLine->clear();
faxLine->clear();
mailLine->clear();
//dateLine->clear();
descriptionContratText->clear();
montantLine->clear();
updateInterface(Modeajouter);
}



void AddressBook::enregistrerContact()
{
QString nom = nameLine->text();
QString prenom = prenomLine->text();
QString adresse = addressText->toPlainText();
QString ville = villeLine->text();
QString tel = telLine->text();
QString fax = faxLine->text();
QString mail = mailLine->text();
QString descriptionContrat = descriptionContratText->toPlainText();
QString montantContrat = montantLine->text();




//QString dateContrat = dateLine->text();



if (nom == "" || prenom == "" || adresse == "" || ville == "" || tel == "" || fax == "" || mail == "" || descriptionContrat == "" ) {
QMessageBox::information(this, tr("Champs vide"),
tr("Entrez vos coordonnées.") );
return;
}

int i=0;i=tel.toInt();
int j=0;j=fax.toInt();
if(i==0)
{QMessageBox::information(this, tr("Retapez le numéro de téléphonne"),
tr("C'est un champ numérique.") );
return;
}
if(j==0)
{QMessageBox::information(this, tr("Retapez le numéro de fax"),
tr("C'est un champ numérique.") );
return;
}




if (currentMode == Modeajouter) {

if (!contacts.contains(nom)) {
contacts.insert(nom, adresse);
QMessageBox::information(this, tr("Ajouté avec succès"),
tr("\"%1\" a été ajouter dans vos contacts.").arg(nom));
} else {
QMessageBox::information(this, tr("Ajout non abouti"),
tr("Désolé, \"%1\" existe déja dans vos contacts.").arg(nom));
return;
}

QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
db.setDatabaseName("monDSN"); // DSN que nous venons de créer.
db.setUserName("amir");
db.setPassword("amir");
db.open();
QSqlQuery query(db);
//"update client set nom=':nom', prenom=':prenom' where id_client=':id_client'"

query.prepare("insert into client (nom,prenom,adresse,tel,fax,ville,mail)"
"values (:nom,:prenom,:adresse,:tel,:fax,:ville,:mail)");
query.bindValue(":nom",nameLine->text());
query.bindValue(":prenom",prenomLine->text());
query.bindValue(":adresse",addressText->toPlainText());
query.bindValue(":tel",telLine->text());
query.bindValue(":fax",faxLine->text());
query.bindValue(":ville",villeLine->text());
query.bindValue(":mail",mailLine->text());
query.exec();


}
}

void AddressBook::annuler()
{
nameLine->setText(oldName);
prenomLine->setText(oldPrenom);
addressText->setText(oldAddress);
villeLine->setText(oldVille);
telLine->setText(oldTel);
faxLine->setText(oldFax);
mailLine->setText(oldMail);
descriptionContratText->setText(oldDescriptionContrat);
//dateLine->setText(oldDateContrat);
montantLine->setText(oldMontant);
updateInterface(Modenavigation);
}

//! [findContact() function]

//! [findContact() function]

void AddressBook::updateInterface(Mode mode)
{
currentMode = mode;

switch (currentMode) {

case Modeajouter:

nameLine->setReadOnly(false);
prenomLine->setReadOnly(false);
nameLine->setFocus(Qt::OtherFocusReason);
addressText->setReadOnly(false);
villeLine->setReadOnly(false);
telLine->setReadOnly(false);
faxLine->setReadOnly(false);
mailLine->setReadOnly(false);
descriptionContratText->setReadOnly(false);
//dateLine->setReadOnly(false);
montantLine->setReadOnly(false);

ajouterButton->setEnabled(false);


enregistrerButton->show();
annulerButton->show();
break;

case Modenavigation:

if (contacts.isEmpty()) {
nameLine->clear();
prenomLine->clear();
addressText->clear();
villeLine->clear();
telLine->clear();
faxLine->clear();
mailLine->clear();
descriptionContratText->clear();
//dateLine->clear();
montantLine->clear();
}

nameLine->setReadOnly(true);
prenomLine->setReadOnly(true);
addressText->setReadOnly(true);
villeLine->setReadOnly(true);
telLine->setReadOnly(true);
faxLine->setReadOnly(true);
mailLine->setReadOnly(true);
descriptionContratText->setReadOnly(true);
//dateLine->setReadOnly(true);
montantLine->setReadOnly(true);
ajouterButton->setEnabled(true);


enregistrerButton->hide();
annulerButton->hide();
break;
}
}


et voila ma fenetre.h

#ifndef ADDRESSBOOK_H
#define ADDRESSBOOK_H

#include <QWidget>
#include <QMap>
//! [include finddialog's header]

QT_BEGIN_NAMESPACE
class QPushButton;
class QLabel;
class QLineEdit;
class QTextEdit;
QT_END_NAMESPACE


class AddressBook : public QWidget
{
Q_OBJECT

public:
AddressBook(QWidget *parent = 0);
enum Mode { Modenavigation, Modeajouter};

public slots:
void ajouterContact();
void enregistrerContact();
void annuler();
//void AjouterContrat();
//! [findContact() declaration]

//! [findContact() declaration]


private:
void updateInterface(Mode mode);


QPushButton *ajouterButton;

//! [findButton declaration]

//! [findButton declaration]
QPushButton *enregistrerButton;
QPushButton *annulerButton;
QLineEdit *nameLine;
QLineEdit *prenomLine;
QTextEdit *addressText;
QLineEdit *villeLine;
QLineEdit *telLine;
QLineEdit *faxLine;
QLineEdit *mailLine;
QTextEdit *descriptionContratText;
QLineEdit *montantLine;
QLineEdit *typeClientLine;


QMap<QString, QString> contacts;
//! [FindDialog declaration]

//! [FindDialog declaration]
QString oldName;
QString oldPrenom;
QString oldAddress;
QString oldVille;
QString oldTel;
QString oldFax;
QString oldMail;
QString oldDescriptionContrat;
QString oldDateContrat;
QString oldMontant;
Mode currentMode;
};

#endif