下面代码怎么不能改变cxGrid行的颜色？

[ys324337347]

procedure Tfrm_Main.GDT_UserListCustomDrawCell(Sender: TcxCustomGridTableView;
  ACanvas: TcxCanvas; AViewInfo: TcxGridTableDataCellViewInfo;
  var ADone: Boolean);
var
  i: Integer;
  PSPID: string;
begin
  PSPID := AViewInfo.GridRecord.DisplayTexts[3];
  if (PSPID = '3') or (PSPID = '4') then
  begin
    mCanvas := ACanvas;
    mCanvas.Brush.Color := clRed;//这儿可以改变
      //TThread.CreateAnonymousThread(SetGline).Start;
    SetGline;
  end;
end;
//下面代码不能改变颜色
procedure Tfrm_Main.SetGline;
var
  I: Integer;
begin
  for I := 0 to 9 do
  begin
    mCanvas.Brush.Color := clRed;
    mCanvas.Refresh;
    Sleep(100);
    mCanvas.Brush.Color := clWhite;
    Sleep(100);
    mCanvas.Refresh;
  end;
end;

怎么不在CustomDrawCell函数里面改变cxGrid行的颜色？