ionic - side-menu doesn't start opened - angularjs

Question

I need to open the menu automatically when navigate to a specific page.
but the event is ignored.
I created the menu controller:
.controller('MenuController', function ($scope, $ionicSideMenuDelegate) {
$scope.toggleLeft = function() {
$ionicSideMenuDelegate.toggleLeft();
}; })
and the specific page controller:
.controller('Sem_ConsultasCtrl', function ($scope) {
$scope.toggleLeft();
$scope.btn = function () { $scope.toggleLeft(); }
})
in my specific page i have a directive ng-click="btn()" wich works (toggles side-menu when click on button).
but if I call ' $scope.toggleLeft(); ' outside of btn() to automatically open the side menu when navigate to specific page nothing happens.

Answer 1

I found the problem:
when I call '$scope.toggleLeft();' outside of btn() the page/template still has not loaded/rendered the DOM. and when I click on button (btn()) works because DOM is already rendered.
to automatically open the side-menu I need to only call '$scope.toggleLeft();' when DOM is already and for achieve that I need to define a Watcher wich do something when occurs some modification to my template:
$timeout(function () {
$scope.toggleLeft();
});
$timeout(function () { //runs after DOM is render} );
This way, is working :)
EDIT:
I was going through my answers and I noticed that this answer was not correct.
calling $timeout triggers a digest cycle that captures differences in the DOM and updates it.
other events like clicking a button or writing in a input text triggers a digest cycle, thats why the changes only happened when clicked the button