In AngularJS, you can create a dropdown list (select box) based on items in an array, or an object.
Using ng-options
You should use the ng-option directive to create a dropdown list, based on an object or an array in AngularJS.
See this example:
<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<select ng-model="selectedName" ng-options="x for x in names">
</select>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.names = ["Java", "PHP", ".Net", "AngularJS", "C/C++"];
});
</script>
</body>
</html>
Note:
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You can also use the ng-repeat directive to make the same dropdown list as ng-options.
See this example:
<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<select>
<option ng-repeat="x in names">{{x}}</option>
</select>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.names = ["Java", "PHP", ".Net", "AngularJS", "C/C++"];
});
</script>
<p>The same example of dropdown list using the ng-repeat directive.</p>
</body>
</html>
ng-options vs. ng-repeat
Although, both can be used for dropdown list, but 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, while 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.
Consider that you have an array of objects:
$scope.cars = [
{model : "Ford Mustang", color : "red"},
{model : "Fiat 500", color : "white"},
{model : "Volvo XC90", color : "black"}
];
Limitation of ng-repeat
The ng-repeat directive has a limitation that the selected value must be a string:
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See this example:
<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<p>Select a car:</p>
<select ng-model="selectedCar">
<option ng-repeat="x in cars" value="{{x.model}}">{{x.model}}</option>
</select>
<h1>You selected: {{selectedCar}}</h1>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.cars = [
{model : "Ford", color : "red"},
{model : "Honda", color : "white"},
{model : "Volvo", color : "black"},
{model : "Hundai", color : "gray"}
];
});
</script>
</body>
</html>
While using the ng-options directive, you can select an object value:
See this example:
<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<p>Select a car:</p>
<select ng-model="selectedCar" ng-options="x.model for x in cars">
</select>
<h1>You selected: {{selectedCar.model}}</h1>
<p>It's color is: {{selectedCar.color}}</p>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.cars = [
{model : "Ford", color : "red"},
{model : "Honda", color : "white"},
{model : "Volvo", color : "black"},
{model : "Hundai", color : "gray"}
];
});
</script>
</body>
</html>
Use data source as an object
We can also use data source as an object.
Consider that you have an object with following key-value pairs:
$scope.cars = {
car01 : "Ford",
car02 : "Honda",
car03 : "Volvo",
car03 : "Hundai",
};
The expression in the ng-options attribute is a bit different for objects:
See this example:
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<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<p>Select a car:</p>
<select ng-model="selectedCar" ng-options="x for (x, y) in cars">
</select>
<h1>You selected: {{selectedCar}}</h1>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.cars = {
car01 : "Ford",
car02 : "Honda",
car03 : "Volvo",
car03 : "Hundai",
}
});
</script>
</body>
</html>
Example2:
The selected value will always be the value in a key-value pair.
The value in a key-value pair can also be an object:
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$scope.cars = {
car01 : {brand : "Ford", model : "Mustang", color : "red"},
car02 : {brand : "Honda", model : "city", color : "white"},
car03 : {brand : "Volvo", model : "XC90", color : "black"},
car04 : {brand : "Hundai", model : "Creta", color : "gray"}
};
See this example:
<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<p>Select a car:</p>
<select ng-model="selectedCar" ng-options="x for (x, y) in cars">
</select>
<h1>You selected: {{selectedCar.brand}}</h1>
<h2>Model: {{selectedCar.model}}</h2>
<h3>Color: {{selectedCar.color}}</h3>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.cars = {
car01 : {brand : "Ford", model : "Mustang", color : "red"},
car02 : {brand : "Honda", model : "city", color : "white"},
car03 : {brand : "Volvo", model : "XC90", color : "black"},
car04 : {brand : "Hundai", model : "Creta", color : "gray"}
}
});
</script>
</body>
</html>
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