How to have a pattern like XXX-XX-XXXX in a string control in a form

I want to have XXX-XX-XXXX pattern automatically genrated in my string control in my form, so, as the user enter's the value e.g. 123456789, it automatically show's 123-45-6789.

In your edit-method you can also use NumberSeq::numInsertFormat() with a format string like "###-##-####"

You can use an edit method with something like (not the same formatting, but that's detail).

edit str editMyString(boolean _set, str _value)
{
    //format string in XXX-XXX-XXX.....
    str _format(str _unformatted)
    {
        str formatted;
        int i,len;
        ;
        len = strlen(_unformatted);
        for(i=1;i<=len;i+=3)
        {
            formatted += (formatted ? '-' : '')+substr(_unformatted,i,3);
        }
        return formatted;
    }
    ;
    if (_set)
    {
        //store string without formatting
        myString = strrem(_value,'-');
    }
    //display a formatted string
    return _format(myString);
}