On 10/30/2014 04:34 PM, Michael Van Canneyt wrote:
On Thu, 30 Oct 2014, Michael Van Canneyt wrote:
On Thu, 30 Oct 2014, Luca Olivetti wrote:
Hello,
TFixedFormatDataSet (ancestor of TSdfDataSet) overrides GetRecNo
(correct) but it does a strange contortion instead of simply returning
FCurRec:
function TFixedFormatDataSet.GetRecNo: Longint;
var
BufPtr: TRecordBuffer;
begin
Result := -1;
if GetActiveRecBuf(BufPtr) then
Result := PRecInfo(BufPtr + FRecInfoOfs)^.RecordNumber;
The records in the buffer may be in a different order than they are
displayed in the grid.
Forget this. I was too quick to respond.
I have done some digging, but cannot find a reason for the current
behaviour.
Easy: Some systems use the recno as some sort of 'bookmark'. And some
people insist that this is the correct behaviour for a dataset. (Note
that for TBufDataset a call to recno is really slow, as it has to
iterate over all records to get the correct recno.)
So some datasets have recno's that uniquely identify a record. I've
tried to unify that once, but that was not easily done. So I decided to
leave this decision to the author of each dataset. Hence the GetRecNo.
But that TDBGrid uses the recno is troublesome... But I don't see a
better solution.
Joost.
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