DBAdvGrid.Cells issue

Hi,I have some question about overwriting on DBAdvGrid's cell with program.
for example,
When column number 3 is edited (OnEditCellDone), same row's column 4,5 and 6 wanted to be overwritten by column 3's data.
 I wrote,
  for i:=4 to 6 do
(dbAdvGrid is connected datasource. Datasource is connected clientdataset. ClientDataset is connected to datasetprovider. DatasetProvider is connected to FireDAC's Query. They All are active.)

But when I edit colun number 3, column 4 to 6 is not overwritten.

How can I code this program?

Please set the data via the DB fields, i.e.

dataset.FiedByName(fieldname).AsString : = yourupdatedvalue;

Thank you for your reply.
I understand.
It is because Cells[c,r] property for DBAdvGrid is read only, so
we must set value directly to DB access component field.

I've coded as your advice.
Completely works well.
Thank you.