QCombobox Click Signal/Event

Hi every one

I've a question to qcombobox. In my application I would add all current Serial ports to the Combo box during the runtime. I tried to update the list, when the user clicks on the Combobox (read only).

After some searching I found something:
http://www.qtcentre.org/threads/946-...from-QCombobox
But the problem is, that the Event function is never called... so where is my fault?

Code:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QQueue>
#include <QLineSeries>
#include <QSerialPortInfo>
 
namespace Ui {
class MainWindow;
}
 
 
class MainWindow : public QMainWindow
{
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    Ui::MainWindow *ui;
 
public slots:
    void vUpdatePortList();
 
protected:
    bool bEventFilter(QObject* o, QEvent* e);
};
 
#endif // MAINWINDOW_H

Code:

#include "mainwindow.h"
 
#include <QLabel>
#include <QTimer>
#include <QChartView>
#include <QValueAxis>
#include <QLineSeries>
#include <QMessageBox>
#include <QSortFilterProxyModel>
 
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow),
{
    ui->setupUi(this);
 
    const QList<QSerialPortInfo> portList(QSerialPortInfo::availablePorts());
    int i = 0;
    foreach (QSerialPortInfo port, portList)
    {
        ui->comboBoxPorts->addItem(port.portName());
        ui->comboBoxPorts->setItemData(i, port.description(), Qt::ToolTipRole);
        i++;
    }
    // Sort List
    QSortFilterProxyModel* proxy = new QSortFilterProxyModel(ui->comboBoxPorts);
    proxy->setSourceModel(ui->comboBoxPorts->model());
    ui->comboBoxPorts->model()->setParent(proxy);
    ui->comboBoxPorts->model()->sort(0);
 
 
    ui->comboBoxPorts->installEventFilter(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
bool MainWindow::bEventFilter(QObject* o, QEvent* e)
{
    if(e->type() == QEvent::Show)
    {
        vUpdatePortList();
        ui->textEdit->append("TRUE");
        return true;
    }
    else
    {
        ui->textEdit->append("FALSE");
        return false;
    }
}
 
void MainWindow::vUpdatePortList()
{
    ui->textEdit->append("Hallo");
}

Isn't there any Click-Signal in QT?

Thank you for helping me.
Best regards, P51D