AngularJS Select Boxes

AngularJS lets you create dropdown lists based on items in an array, or an object.

Creating a Select Box Using ng-options

If you want to create a dropdown list, based on a object or an array in AngularJS, you should use the ng-option directive:

Example

var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.names = ["Emil", "Tobias", "Linus"];
});

</script>

Try it Yourself »

ng-options vs ng-repeat

You can also use the ng-repeat directive to make the same dropdown list:

Example

Try it Yourself »

Because the ng-repeat directive repeats a block of HTML code for each item in an array, it can be used to create options in a dropdown list, but the ng-options directive was made especially for filling a dropdown list with options, and has at least one important advantage:

Dropdowns made with ng-options allows the selected value to be an object, while dropdowns made from ng-repeat has to be a string.

What Do I Use?

Assume you have an array of objects:

$scope.cars = [
    {model : "Ford Mustang", color : "red"},
    {model : "Fiat 500", color : "white"},
    {model : "Volvo XC90", color : "black"}
];

The ng-repeat directive has it's limitations, the selected value must be a string:

Example

Using ng-repeat:

<select ng-model="selectedCar">
<option ng-repeat="x in cars" value="{{x.model}}">{{x.model}}</option>
</select>

<h1>You selected: {{selectedCar}}</h1>

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When using the ng-options directive, the selected value can be an object:

Example

Using ng-options:

<select ng-model="selectedCar" ng-options="x.model for x in cars">
</select>

<h1>You selected: {{selectedCar.model}}</h1>
<p>It's color is: {{selectedCar.color}}</p>

Try it Yourself »

When the selected value can be an object, it can hold more information, and your application can be more flexible.

We will use the ng-options directive in this tutorial.

The Data Source as an Object

In the previous examples the data source was an array, but we can also use an object.

Assume you have an object with key-value pairs:

$scope.cars = {
    car01 : "Ford",
    car02 : "Fiat",
    car03 : "Volvo"
};

The expression in the ng-options attribute is a bit different for objects:

Example

Using an object as the data source, x represents the key, and y represents the value:

<select ng-model="selectedCar" ng-options="x for (x, y) in cars">
</select>

<h1>You selected: {{selectedCar}}</h1>

Try it Yourself »

The selected value will always be the value in a key-value pair.

The value in a key-value pair can also be an object:

Example

The selected value will still be the value in a key-value pair, only this time it is an object:

$scope.cars = {
car01 : {brand : "Ford", model : "Mustang", color : "red"},
car02 : {brand : "Fiat", model : "500", color : "white"},
car03 : {brand : "Volvo", model : "XC90", color : "black"}
};

Try it Yourself »

The options in the dropdown list does not have be the key in a key-value pair, it can also be the value, or a property of the value object: