OnCalcFields and RecNo

[mr.amit.g]

Hi,

I'm trying ZeosLib...

I'm doing this in my demo application...

Code: Select all

procedure dmDatabase.MessagesCalcFields(DataSet: TDataSet);
begin
  MessagesNO.asInteger := Messages.RecNo;
end;

MessagesNO is a Calculated field which I'm using for giving no to the messages.

It gives strange results in DBGrid...

This works with IBX...

What is going wrong?

[gto]

hum... maybe the RecNo isn't updated when calcfields is executed

An idea is to deal with some database field (something like add another field called "code", "index"..) or even access the RecNo property directy, as you don't make any changes to it

[zippo]

Have you traced?

Add a line like this

ShowMessage(IntToStr(Messages.RecNo));

But my suggestion is that you use the operation once, not on every calculation. Just to be sure. It' ssomehow innatural form me to calculate the current row basing onto previous rows.. (BTW: Some people say thet RecNo is very slow) If I were you I would create something like this.

AfterOpen event

Code: Select all

begin
  DataSet.DisableControls;
  while not DataSet.Eof do begin
    DataSet.Edit;
    DataSet.FieldByName('MessagesNo').AsInteger := DataSet.RecNo;
    DataSet.Next;
  end;
  DataSet.DisableControls;

It's executed just once, so should be faster. ah, and MessagesNO shouldn't be calculated anymore.

[subnike]

I find the code in ZAbstractRODataset.pas line:1678

Code: Select all

function TZAbstractRODataset.GetRecNo: Longint;
begin
  if Active then
    UpdateCursorPos;
  Result := CurrentRow;
end;

Why use UpdateCursorPos?
When I obtain RecNO also setting up its RecNO in the meantime, such as whether have a little aoddiness.

And I remark

Code: Select all

function TZAbstractRODataset.GetRecNo: Longint;
begin
//  if Active then
//    UpdateCursorPos;
  Result := CurrentRow;
end;