def refresh(self):
        """
        Resets the data for this navigator.
        """
        self.setUpdatesEnabled(False)
        self.blockSignals(True)
        self.clear()
        tableType = self.tableType()
        if not tableType:
            self.setUpdatesEnabled(True)
            self.blockSignals(False)
            return
        
        schema = tableType.schema()
        columns = list(sorted(schema.columns(),
                              key=lambda x: x.name().strip('_')))
        for column in columns:
            XOrbColumnItem(self, column)
        
        self.setUpdatesEnabled(True)
        self.blockSignals(False)
Resets the data for this navigator.