I have this class:
Qt Code: 
  1. #include <QTableWidgetItem>
  2. #include <QSignalMapper>
  3. #include <QCompleter>
  4. #include <QSqlError>
  5. #include <QSqlTableModel>
  6.  
  7. #include "bill.h"
  8.  
  9. #include <QMessageBox>
  10.  
  11. PrintBill::PrintBill(QWidget *parent) : QDialog(parent),
  12.                                                                     ui(new Ui::PrintBill)
  13. {
  14.     ui->setupUi(this);
  15.  
  16.     ui->billTableWidget->setSelectionBehavior (QAbstractItemView::SelectItems );
  17.     ui->billTableWidget->setSelectionMode( QAbstractItemView::ExtendedSelection );
  18.     ui->billTableWidget->setRowCount(1);
  19.     ui->billTableWidget->setColumnCount (5);
  20.     ui->billTableWidget->setHorizontalHeaderLabels (labels);
  21.     ui->billTableWidget->setColumnWidth (0, 63);
  22.     ui->billTableWidget->setColumnWidth (1, 400);
  23.     ui->billTableWidget->setColumnWidth(2, 100);
  24.     ui->billTableWidget->setColumnWidth(3, 63);
  25.     ui->billTableWidget->setColumnWidth(4, 85);
  26.  
  27.     QLineEdit *product = new QLineEdit;
  28.     ui->billTableWidget->setCellWidget(0, 1, product);
  29.     sigMapper = new QSignalMapper(this);
  30.     connect(product, SIGNAL(textEdited(QString )), sigMapper, SLOT(map()));
  31.     sigMapper->setMapping(product, txt);
  32.     connect(sigMapper, SIGNAL(mapped(QString )), this, SLOT(suggestItem()));
  33.  
  34. }
  35.  
  36. void PrintBill::printBill()
  37. {
  38. }
  39.  
  40. void PrintBill::suggestItem()
  41. {
  42.     QLineEdit *product = static_cast<QLineEdit *>(ui->billTableWidget->cellWidget(0, 1));
  43.  
  44.   /*  sqlQuery = "SELECT Name FROM Items WHERE Name LIKE '%" + product->text() + "%'";
  45.     query.exec(sqlQuery);
  46.     rec = query.record();
  47.  
  48.     QMessageBox msg;
  49.     msg.setText(product->text() +  QString::number(query.numRowsAffected()));
  50.     //msg.exec();
  51.     while(query.next())
  52.      {
  53.         items << query.value(rec.indexOf("Name")).toString();
  54.         msg.setText( query.value(rec.indexOf("Name")).toString());
  55.         msg.exec();
  56.      }
  57. */
  59.     QCompleter suggestions(items);
  60.     suggestions.setCaseSensitivity(Qt::CaseInsensitive);
  61.     suggestions.setModel(model);
  62.     suggestions.setCompletionColumn(1);
  63.     suggestions.setCompletionMode(QCompleter::PopupCompletion);
  64.     model->setTable("Items");
  65.     model->select();
  66.     model->setFilter("Name LIKE '%" + product->text() + "%'");
  67.  
  68.     product->setCompleter(&suggestions);
  69. }
  70.  
  71. PrintBill::~PrintBill()
  72. {
  73.     delete ui;
  74. }
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Now, if I type any thing, no data appear in the QLineEdit, the connection is steal open. I tried also query.numRowsAffected() but always return -1.