Subject Re: how left() works in dbase 11 plus From Mervyn Bick <invalid@invalid.invalid> Date Sun, 30 May 2021 09:25:41 +0200 Newsgroups dbase.getting-started On 2021/05/30 08:03, AGOSTINHO wrote: > Dear group, > > If I want to test an user's input in DBASE DOS I do somethng like this > ?left(ccode,4) > > I've tried it in this function but I get an error > also need to make sure that the input are numbers only. > > function ENTRYFIELD4_onKey(nChar, nPosition,bShift,bControl) >        form.clients1.params['ag'] = '%'+this.value+'%' >        form.clients1.requery() >        if form.entryfield1.value.left(4) >                    do something >       endif >       return Error messages usually, but unfortunately not always, point to exactly what is wrong.  It does help though if you give us the wording of the error message. Set the value property of entryfield4 to Integer.  This will ensure that the only digits can be entered. Adding '%' to the start and end of the value will automatically convert the result to character so that the requery() will work properly. The left() function only works with strings, not numbers.  You can test for a 4 digit number as follows.       if form.entryfield4.value > 999 and form.entryfield4.value < 10000          do something          return At present you onKey event handler requeries and fetches a new rowset as each digit is entered.  If you are not going to "do something" until you have entered 4 digits then the following may be a better option     function ENTRYFIELD4_onKey(nChar, nPosition,bShift,bControl)        if form.entryfield4.value > 999           form.clients1.params['ag'] = '%'+this.value+'%'           form.clients1.requery()          do something        endif        return This will requery as soon as the 4th digit is entered.  If you want to prevent further digits from being entered then add the 'and form.entryfield4.value < 10000' to the test or set the entryfield's picture property to'9999'. Mervyn.