Select value not selected in Angularjs - angularjs

Question

I have this html markup:
<div ng-repeat="prop in props" style="margin-bottom: 10px;">
<label class="col-md-4 control-label">Property {{$index + 1}} ({{prop.AddressLine1}})</label><div class="col-md-8">
<select ng-model="prop.Grade" class="form-control" ng-options="opt.name for opt in propGradings track by opt.id"> <option ng-selected="{{option.id == prop.Grade}}" ng-repeat="option in propGradings" ng-value="{{option.id}}">{{option.name}}</option> </select>
</div>
</div>
This static array to fill in the dropdown:
$scope.propGradings = [{ name: "1", id: 1 }, { name: "2", id: 2 }, { name: "3", id: 3 }, { name: "4", id: 4 }];
I'm able to load the items in the dropdown, but I'm not able to preselect the correct value based on the prop.Grade value.
HTML Output:
Any idea what am I doing wrong?

Answer 1

When selecting options from a dropdown, type matters for binding purposes. When using ng-options, you can use as to bind something to the model as a non-string value. In your case, you may want to bind to the integer value of the id.
Syntax: select as label for value in array
> select: The value that gets bound to ng-model
> label: What value visibly shows up in the dropdown
> value: Current item in array
> array: Data source for generating the options
Example of binding to an integer value:
var app = angular.module("myApp", []);
app.controller("myCtrl", function ($scope) {
$scope.props = [{Grade: 1}];
$scope.propGradings = [{ name: "1", id: 1 }, { name: "2", id: 2 }, { name: "3", id: 3 }, { name: "4", id: 4 }];
});
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="myApp" ng-controller="myCtrl">
Binding with an integer value:
<div ng-repeat="prop in props" style="margin-bottom: 10px;">
<label class="col-md-4 control-label">Property {{$index + 1}} ({{prop.AddressLine1}})</label>
<div class="col-md-8">
<select ng-model="prop.Grade" class="form-control" ng-options="opt.id as opt.name for opt in propGradings">
<option ng-selected="{{option.id == prop.Grade}}" ng-repeat="option in propGradings" ng-value="{{option.id}}">{{option.name}}</option>
</select>
</div>
</div>
</div>
Example of binding to a string value:
var app = angular.module("myApp", []);
app.controller("myCtrl", function ($scope) {
$scope.props = [{Grade: "1"}];
$scope.propGradings = [{ name: "1", id: 1 }, { name: "2", id: 2 }, { name: "3", id: 3 }, { name: "4", id: 4 }];
});
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="myApp" ng-controller="myCtrl">
Binding with a string value:
<div ng-repeat="prop in props" style="margin-bottom: 10px;">
<label class="col-md-4 control-label">Property {{$index + 1}} ({{prop.AddressLine1}})</label>
<div class="col-md-8">
<select ng-model="prop.Grade" class="form-control" ng-options="opt.name as opt.name for opt in propGradings">
<option ng-selected="{{option.id == prop.Grade}}" ng-repeat="option in propGradings" ng-value="{{option.id}}">{{option.name}}</option>
</select>
</div>
</div>
</div>