c# - MVC4 ExceptionContext ExceptionHandled Property no try catch block ELMAH -

i trying install , test elmah fist time. think have setup correctly. know elmah designed log unhandled exceptions. use standard template mvc 4 application generated visual studio 2012

in homecontroler class throw error without try , catch block

public actionresult about() {     // throw test error can see handled elmah     // test go ~/elmah.axd page see if error being logged correctly     throw new exception("a test exception elmah");      return view(); } 

in opinion unhandled exception.

further use handleerrorwithelmahattribute class handle error. construct shown in many elmah tutorials posted here:

how elmah work asp.net mvc [handleerror] attribute?

the code bothers me is:

public override void onexception(exceptioncontext context) {     base.onexception(context);      var e = context.exception;     if (!context.exceptionhandled   // if unhandled, logged anyhow         || raiseerrorsignal(e)      // prefer signaling, if possible         || isfiltered(context))     // filtered?         return;          logexception(e); } 

in if statement property contect.exceptionhanled checked. property set true, thrown error not logged.

can explain why set true while there no try-catch.

best regards, sebastian