TAdvStringGrid - Howto cancel AppendOnArowDown ?

VCL TMS VCL UI Pack
1

Hi.


Having a grid with AppendOnArrowDown set to true I can use OnCanAddRow event, to make sure the user has input enough data to allow a new row to be appended.
This works OK - but I need to remove then newly inserted row if the user chooses to "arrow up" , tab to next control or just click on another row in the grid.

Checking with OnRowChanging or OnRowUpdate I can decide if the newly inserted row is obsolete ... but I cannot use DeleteRows to get rid of it. This will start an endless loop calling OnRowChanging or OnRowUpdate multiple times.

How can I achieve this simple task?
2

RemoveRows .... not DeleteRows :-)


3 

procedure TForm1.AdvStringGrid1RowChanging(Sender: TObject; OldRow, NewRow: Integer; var Allow: Boolean);
begin
  if (AdvStringGrid1.Cells[1, OldRow] = '') and // first check ...
    (AdvStringGrid1.Cells[2, OldRow] = '') then
  begin
    if AdvStringGrid1.Cells[1, NewRow] <> '' then // second check - if needed.
    begin
      AdvStringGrid1.OnRowChanging := nil;
      AdvStringGrid1.RemoveRows(OldRow,1); // RemoveRows to cancel appended or inserted row.
      AdvStringGrid1.OnRowChanging := AdvStringGrid1RowChanging;
    end;
  end;
end;

Not the best solution - but it will do the trick.

4

OnRowChanging is triggered while a row is about to be changed so it is expected this will cause problems when you execute code that affects rows from OnRowChanging. Temporarily removing the event handler is indeed a possible solution (or setting a global flag to stop further processing of the event)

5
Yes it works - and is needed. The idea of a global flag is a solution - but I think I'm better off with this.

Suggestion:
Stopping even handlers could be built into BeginUpdate / EndUpdate.
Or as others do - implement a new method - BeginFullUpdate / EndFullUpdate.