Class: TEgFireGrid
property OnExportProgress: TEgFireGridExportProgressEvent;
TEgFireGridExportProgressEvent = procedure(Sender: TObject; var PercentDone: Integer) of object;Reports the progress of ExportToXLSX
as a percentage: 0 before the first row, then at most once per whole
percent while the dataset knows its record count, and 100 once the file
is written (not when the export fails). PercentDone is a
var parameter only for compatibility with
TEgDBGridEx; a value assigned to it is ignored.
The handler runs in the thread that called ExportToXLSX,
while the export is running; a progress bar updated there is repainted
only if the handler lets the application process its messages.