At 02:11 AM 18/09/2007, you wrote:

>Hello all.
>Well i have another problem with blob fields. :-(
>I have a procedure that uses a dataset (a TIBOQuery), finds the
>blobfield by name and saves it to a stream, or so i thought! I realy
>dont know why but the TBlobField.SaveToStream(TMemoryStream) does
>nothing. But if instead i use TBlobField.SaveToFile('c:\file.txt') it
>works perfectly.
>
>Here's the code:
>
>procedure TUser.LoadDefs;
>var
> i: integer;
> ms: TMemoryStream;
>begin
> // FDefsDataSet is a TDataSet from the User class. When the user
> // class is initiated the FDefsDataSet field has its value assigned
> // to a TIBOQuery.
>
> if (FDefsDataSet.RecordCount = 0) then Exit;
>
> FDefsDataSet.First;
> ms := TMemoryStream.Create;
> for i := 0 to (FDefsDataSet.RecordCount-1) do
> begin
> FDefinitions.Clear;
> with FDefinitions.Add do
> begin
> FClassName := FDefsDataSet.FieldByName('CLASS').AsString;
> (FDefsDataSet.FieldByName('DEF') as TBlobField).SaveToStream
>(ms);
> FUserData := FDefsDataSet.FieldByName('AUDIT_DATA').AsDateTime;
> FUserDsc := FDefsDataSet.FieldByName('AUDIT_USER_DSC').AsString;
> end;
> FDefsDataSet.Next;
> end;
>end;
>
>Any help on this matter would be mutch appreciated!

Supposedly your FDefinitions structure has a compatible class within
it, to which the stream's contents could be assigned, but your
procedure does not do anything with the stream after filling its
buffer. It is just a local memory buffer that is not associated with
anything, e.g., a compatible TGraphic, TMemo, or whatever member
object inside the structure.

I won't attempt to guess what's intended here, but one supposes that
your FDefinitions.Clear method actually stores the current contents
of its member buffers somewhere before clearing them. Otherwise, it
seems a bit pointless to loop through a dataset doing all this work
on every record, if the ultimate objective is to fill the structure
with the data from the last record.

Helen