I want to reset Line No. when line is deleted, how can I do that?

Vesna_1

I want to reset Line No. when line is deleted, how can I do that?
Can I use OnDelete trigger and how?
When I delete all records and want to create new, Line No. is not starting from 1. It starts from last number of deleted records.

kvb

you can override default "Line No." value (it is incrementing with every new record no matter what)
Create function:

GetNewLineNo () : integer 
lr_SomeRec.SETRANGE("Primary Key Field", Rec."Primary Key Field")
IF lr_SomeRec.FINDLAST
  THEN EXIT(lr_SomeRec."Line No." + 1)
  ELSE EXIT(0)

Add this code to the last line of the OnInsert trigger of table:

"Line No." := GetNewLineNo;

not the best practice at all but sometimes we have to do something just nice for customer, aren`t we?

Vesna_1

AutoIncrement is set to Yes

logger

Honestly speaking, it is a REALLY BAD IDEA to manually change value in AutoIncrement field. I faced with the similar issue recently, when developer tried to manually set numbers to AutoIncrement field, and we had many troubles with users. In detailed way, you can read http://bpsoftware.com/2012/12/01/microsoft-dynamics-nav-permission-error-set-identity_insert/

IMHO, as described on the link above, you have 2 options:
1. Leave AutoIncrement field alone, not trying to change it manually in any way;
2. Change AutoIncrement Property to false, and manage this field manually.