HTML SELECT
element with angular data-binding.
ngOptions
The ngOptions
attribute can be used to dynamically generate a list of <option>
elements for the <select>
element using the array or object obtained by evaluating the
ngOptions
comprehension_expression.
When an item in the <select>
menu is selected, the array element or object property
represented by the selected option will be bound to the model identified by the ngModel
directive.
ngModel
compares by reference, not value. This is important when binding to an
array of objects. See an example in this jsfiddle.
Optionally, a single hard-coded <option>
element, with the value set to an empty string, can
be nested into the <select>
element. This element will then represent the null
or "not selected"
option. See example below for demonstration.
ngOptions
provides an iterator facility for the <option>
element which should be used instead
of ngRepeat when you want the
select
model to be bound to a non-string value. This is because an option element can only
be bound to string values at present.
select as
will bind the result of the select as
expression to the model, but
the value of the <select>
and <option>
html elements will be either the index (for array data sources)
or property name (for object data sources) of the value within the collection.
Note: Using select as
together with trackexpr
is not recommended.
Reasoning:
value
, with the purpose of preserving the selection,
(to item
in this case)track by
to the values in the array, e.g.
In the example: [1,2]track by
to the already selected value in ngModel
:
In the example: this is not possible, as track by
refers to item.id
, but the selected
value from ngModel
is {name: aSubItem}
.<select
ng-model=""
[name=""]
[required=""]
[ng-required=""]
[ng-options=""]>
...
</select>
Param | Type | Details |
---|---|---|
ngModel | string |
Assignable angular expression to data-bind to. |
name
(optional)
|
string |
Property name of the form under which the control is published. |
required
(optional)
|
string |
The control is considered valid only if value is entered. |
ngRequired
(optional)
|
string |
Adds |
ngOptions
(optional)
|
comprehension_expression |
in one of the following forms:
Where:
|
<script>
angular.module('selectExample', [])
.controller('ExampleController', ['$scope', function($scope) {
$scope.colors = [
{name:'black', shade:'dark'},
{name:'white', shade:'light'},
{name:'red', shade:'dark'},
{name:'blue', shade:'dark'},
{name:'yellow', shade:'light'}
];
$scope.myColor = $scope.colors[2]; // red
}]);
</script>
<div ng-controller="ExampleController">
<ul>
<li ng-repeat="color in colors">
Name: <input ng-model="color.name">
[<a href ng-click="colors.splice($index, 1)">X</a>]
</li>
<li>
[<a href ng-click="colors.push({})">add</a>]
</li>
</ul>
<hr/>
Color (null not allowed):
<select ng-model="myColor" ng-options="color.name for color in colors"></select><br>
Color (null allowed):
<span class="nullable">
<select ng-model="myColor" ng-options="color.name for color in colors">
<option value="">-- choose color --</option>
</select>
</span><br/>
Color grouped by shade:
<select ng-model="myColor" ng-options="color.name group by color.shade for color in colors">
</select><br/>
Select <a href ng-click="myColor = { name:'not in list', shade: 'other' }">bogus</a>.<br>
<hr/>
Currently selected: {{ {selected_color:myColor} }}
<div style="border:solid 1px black; height:20px"
ng-style="{'background-color':myColor.name}">
</div>
</div>
it('should check ng-options', function() {
expect(element(by.binding('{selected_color:myColor}')).getText()).toMatch('red');
element.all(by.model('myColor')).first().click();
element.all(by.css('select[ng-model="myColor"] option')).first().click();
expect(element(by.binding('{selected_color:myColor}')).getText()).toMatch('black');
element(by.css('.nullable select[ng-model="myColor"]')).click();
element.all(by.css('.nullable select[ng-model="myColor"] option')).first().click();
expect(element(by.binding('{selected_color:myColor}')).getText()).toMatch('null');
});