Uses OnGraphicError
to report a picture field whose bytes cannot be decoded, which otherwise
only shows as a cell with the field’s text instead of the picture.
Scenario
The Photo column shows the products’ pictures. A damaged
picture, or one in a format the platform cannot decode, is written to
the application’s log with the product it belongs to.
procedure TForm1.Grid1GraphicError(Sender: TObject; Column: TEgFireGridColumn; const Msg: string);
begin
LogMemo.Lines.Add(Format('%s: picture of column %s not shown (%s)',
[FormatDateTime('hh:nn:ss', Now), Column.Title.Caption, Msg]));
end;
Why it works this way
Reported once: the grid remembers the bytes it
failed to decode, so the same picture is not reported again at every
refresh; a different picture in the same cell is.
No row parameter: the event says which column, not
which row; pictures are decoded while the rows are drawn, so the
dataset’s current record is not the row of the picture. To show which
product it is, use the cell itself: a cell whose picture failed shows
its text instead, and a decoded picture replaces the text, so an OnBeforeDrawCell
handler that sets the Photo cells’ Text to, say,
'Bad picture: <var>Name</var>' shows it only on
the rows whose picture failed.
Plain BLOB fields read as pictures with DetectBlobImages
are not reported: a BLOB that is not a picture is expected.
The formats decoded are those of the platform: JPEG, PNG, BMP and
GIF on both, and the others each platform supports.