Try this:

lnYear=YEAR(DATE())
SELECT MAX(billno) from billinfo WHERE YEAR(billinfo.billdate)=lnYear INTO ARRAY laAarray
if _tally=0
  laArray=1
  thisform.text1.value=(RIGHT(STR(lnYear),4),2) + '_'+RIGHT(STR(10000+1,5),4))
else
  thisform.text1.value=(RIGHT(STR(YEAR(billinfo.billdate),4),2) + '_'+RIGHT(STR(10000+billinfo.billno+1,5),4))
endif
INSERT  INTO  billinfo(billno,billdate) VALUES (val(right(thisform.text1.Value,4)),DATE())

>hi,
>ok ,i try ,it works,
>
>i try to change mypc calander to 2005 to get new bill as 05_0001
>but i get ex...05_0009.
>

>SELECT MAX(billno) from billinfo INTO ARRAY laAarray
>thisform.text1.value=(RIGHT(STR(YEAR(billinfo.billdate),4),2) + '_'+RIGHT(STR(10000+billinfo.billno+1,5),4))
>INSERT  INTO  billinfo(billno,billdate) VALUES (val(right(thisform.text1.Value,4)),DATE())
>

>thanks.
>m.qasem
>
>>Not that I can think of which is foolproof. In theory you can set traps in KeyPress, but it would be a lot of work.
>>Why not have two textboxes very close, one with 04_ which is readonly, and the other with only the billno?
>>
>>>hi,
>>>thank you so much,it works.
>>>any way to let 04_ at mytext all the time at myform.
>>>just can i insert billno as 0003 at my text.
>>>
>>>thanks.
>>>best regards.
>>>m.qasem
>>>
>>>>

>>>>inyearofbill=2000+VAL(LEFT(thisform.text1.Value,2))
>>>>inbillno=INT(VAL(SUBSTR(thisform.text1.value,4)))
>>>>IF USED('billinfo')
>>>>  SELECT Billinfo
>>>>ELSE
>>>>  SELECT 0
>>>>  USE billinfo AGAIN && Billinfo may be used in another work area with another alias, so use AGAIN to be safe
>>>>ENDIF
>>>>LOCATE for YEAR(billdate)=inyearofbill AND billno=inbillno
>>>>IF FOUND()
>>>>  thisform.text2.value=name
>>>>  .
>>>>  .
>>>>  .
>>>>ELSE
>>>>  =MESSAGEBOX("not found")
>>>>endif
>>>>

>>>>>hi,
>>>>>thank you very much,it works
>>>>>i need to change this code with locate or scan as under
>>>>>

>>>>>
>>>>>inyearofbill=2000+VAL(LEFT(thisform.text1.Value,2))
>>>>>inbillno=INT(VAL(SUBSTR(thisform.text1.value,4)))
>>>>>SELECT * from billinfo WHERE YEAR(billdate)=inyearofbill AND billno=inbillno INTO CURSOR curbilldata
>>>>>************
>>>>>LOCATE for YEAR(billdate)=inyearofbill AND billno=inbillno
>>>>>IF FOUND()
>>>>>thisform.text2.value=name
>>>>>.
>>>>>.
>>>>>.
>>>>>ELSE
>>>>>=MESSAGEBOX("not found")
>>>>>endif
>>>>>********************
>>>>>

>>>>>
>>>>>thanks.
>>>>>m.qasem
>>>>>
>>>>>>

>>>>>>INSERT  INTO  billinfo(billno,billdate) VALUES (val(right(thisform.text1.Value,4)),DATE())
>>>>>>

>>>>>>Remember that the value showed in thisform.text1.Value, 04-0001, is ONLY ment to show nicely, it is not the actual billno.
>>>>>>
>>>>>>>hi,
>>>>>>>thank you very much,it works
>>>>>>>i try to insert myvalue as under ,but i get error messag(data type mismatch)
>>>>>>>

>>>>>>>INSERT  INTO  billinfo(billno,billdate) VALUES (thisform.text1.Value,DATE())
>>>>>>>

>>>>>>>thanks.
>>>>>>>m.qasem
>>>>>>>
>>>>>>>>Try this.
>>>>>>>>
>>>>>>>>thisform.text1.value=RIGHT(STR(YEAR(DATE()),4),2) + '_'+RIGHT(STR(10000+(billinfo.billno+1),5),4)