if you want to control the DetailBand, the method like this:
//Example
TableDBDEMOS animals.dbf)
procedure TForm2.QRBand1BeforePrint(Sender: TQRCustomBand;
var PrintBand: Boolean);
begin
PrintBand:=Table1.FieldByName('Size').AsInteger>10;
end;
Otherwise, if you want one band or one label etc. use :
(Sender:Band,label,) .Enabled:=False;