inserting a row in a QTableWidget doesn t work!

[adonis]

Hi everybody,
i want to insert a row in QTableWidget with a buttonclick.

class CoordinateTable:public QTableWidget
{
       Q_OBJECT
public:
        CoordinateTable(QWidget *parent=0);
 
private slots :
  void addrow();
 
};
 
 
CoordinateTable::CoordinateTable(QWidget *parent)
    : QTableWidget(parent)
{   setColumnCount(2);
    setRowCount(2);
    };
  void  CoordinateTable::addrow()
   {
     int row = CoordinateTable::rowCount();
    CoordinateTable:: insertRow(row);
 
        };

class CoordinateTable:public QTableWidget
{
       Q_OBJECT
public:
        CoordinateTable(QWidget *parent=0);

private slots :
  void addrow();

};

     
CoordinateTable::CoordinateTable(QWidget *parent)
    : QTableWidget(parent)
{   setColumnCount(2);
    setRowCount(2);
    };
  void  CoordinateTable::addrow()
   {
     int row = CoordinateTable::rowCount();
    CoordinateTable:: insertRow(row);

        };

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In main

....
CoordinateTable  *tableWidget = new  CoordinateTable;
 QObject::connect(okbutton, SIGNAL(clicked()),
                            tableWidget ,SLOT(addrow()));

....
CoordinateTable  *tableWidget = new  CoordinateTable;
 QObject::connect(okbutton, SIGNAL(clicked()),
                            tableWidget ,SLOT(addrow()));

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okbutton is a QT4 QPushButton.
Nothing happens when i click the button and i dont understand why.