How to create button to addition every lines in DBGrid Delphi 7

Question

how to make button on delphi 7 to execute addition with all data in dbgrid delphi. for example i have database table with 3 coloumns show in dbgrid,

[CODE_NUMBER][ITEMS NAME][STOCK][NEW_STOCK]
 001          Rackets       1         5
 002          Sports Shoes  2         5
 003          Golf Hat      3         5 
 ... etc

How to create button when i click it, then dbgrid start addition

[STOCK] = [STOCK]+[NEW_STOCK]

after count in the first line, move to second line do the same addition and so on until the end of the record in dbgrid and delete data in [NEW_STOCK] coloumn. i've try with

if dbgrid1.fieldbyname('Code').value <> 0 then
begin
dbgrid1.fieldbyname('Stock').value := dbgrid1.fieldbyname('Stock').value + dbgrid1.fieldbyname('NEW_STOCK').value;
dbgrid1.next;

but only affect in the first line, nothing happen with the next lines in dbgrid

It is not 100% clear to me what you are trying to achieve, but i think perhaps what you need is a calculated field. The calculated field is defined in the dataset and allows you to define the calculation in Delphi code. Look at OnCalcFields in the help. — Hugh Jones
@Hugh Jones, Thanks for your attention, my problem is solved, — Arie Prasetyo

Accolade Accolade · Accepted Answer · 2016-03-05T18:25:19

To change data in dbgrid, you should use it's corresponding dataset, i.e.:

with dbgrid1.DataSource.DataSet do begin
  Edit;
  Fields.fieldbyname('Stock').value := Fields.fieldbyname('Stock').value + Fields.fieldbyname('NEW_STOCK').value;
  Post;
  Next;
end;

How to create button to addition every lines in DBGrid Delphi 7

2 Answers