Questions about onKeyPress

Hello all,

I want to allow the user only to enter at most 6 characters in the cell of table.
Here is my implementation:

// class PlanPointTable : public FXTable
long PlanPointTable::onKeyPress(FXObject *sender, FXSelector sel, void* ptr)
{
        ...
        FXTableItem *item = getItem(current.row, current.col);
        FXString str = item->getText();

        if (str.length() > 5)
       {
            // do nothing
           return 1;
        }

        ...
        return 1;
}

The problem is that during the entering procedure, the returned value of the str is always EMPTY
until I press ENTER key.

Is there a method that I can get the entered text in the cell on real time?

Thank you