Alert question

[antonio]

On MT4  I had the code for trigger "alert once on the bar current":

static bool TriggerOnlyThisBar;

...............

............... 

  if (......trigger condition......) &&  TriggerOnlyThisBar!=Bars

    {
      Alert(Symbol()," TEST ");
       TriggerOnlyThisBar = Bars;
     }

on mt5 I have replaced Bars (MT4) with Bars (symbol (), period_current) but does not work.

Someone explains to me where it is error?

Thanks to all.