ng-select with lazy population - angularjs

Question

It's an edit form with parent record first populated then dependent select list is populated, and then it's expected the value from parent record pre-select the combo box.
html
<select ng-model="data.trackId" >
<option ng-repeat="track in tracks" value="{{track.id}}">{{track.name}}</option>
initial result once parent record is pulled.
if(data) {
this.$scope.data.id = data.id;
this.$scope.data.name = data.name;
this.$scope.data.room = data.room;
this.$scope.data.start = data.start;
this.$scope.data.end = data.end;
this.$scope.data.dayId = data.day_id;
this.$scope.data.trackId = data.track_id;
this.$scope.data.color = data.color;
this.$scope.data.description = data.description;
this.$scope.$apply();
this.$element[0].removeAttribute("style");
}
//later track results were pulled
trackResult: function(data, status, headers, config) {
for(var i=0; i<data.length; i++) {
this.$scope.tracks.push(data[i]);
}
this.$scope.$apply();
},
Problem:
List gets populated from the second call trackResult but default value from the $scope.trackId never sets the combo box to a value.
Edit: Controller Body
controller: function($scope, $element) {
var self = this;
this.$scope = $scope;
this.$element = $element;
this.$scope.data = {};
this.$scope.days = [];
this.$scope.tracks = [];
this.$scope.submit = function() {self.submit()};
this.$scope.cancel = function() {self.cancel()};
},

Answer 1

Edit : Updated with setting the data from outside the scope (OP request)
Use ng-options & ng-model
this is how i think it should be done in angularjs.
use the built in databinding capabilities to simplify your code and make it less complicated
for binding a list into a <select> and controlling the selected item, this snippet below should do the trick.
http://jsfiddle.net/72em40j4/
js
var myapp = angular.module('myapp', []);
myapp.controller('Ctrl', function ($scope) {
$scope.options = [];
$scope.selectedOption = null;
});
html
<script>
function clickFromOutside() {
var controllerElement = document.getElementById('container');
var controllerScope = angular.element(controllerElement).scope();
var firstTrack = {
id: 1,
first: 'First',
last: 'Track'
};
var secondTrack = {
id: 2,
first: 'Second',
last: 'Track'
};
controllerScope.options.push(firstTrack);
controllerScope.options.push(secondTrack);
controllerScope.selectedOption = secondTrack;
controllerScope.$apply();
}
</script>
<button onclick="clickFromOutside();">outside</button>
<div ng-app="myapp">
<fieldset id="container" ng-controller="Ctrl">
<select ng-options="p.first + ' ' + p.last for p in options" ng-model="selectedOption"></select> <pre>{{ selectedOption }}</pre>
</fieldset>
</div>