AngularJs - SELECT中的ng-model

Question

JSfiddle

Problem:

I have a SELECT-element in my page, which is filled in with an ng-repeat . It also has a ng-model which has a default value.

When I change the value, the ng-model adapts, that's ok. But the dropdown-list shows an empty slot at launch, where it should have the item with the default value selected instead.

Code

<div ng-app ng-controller="myCtrl">
    <select class="form-control" ng-change="unitChanged()" ng-model="data.unit">
         <option ng-repeat="item in units" ng-value="item.id">{{item.label}}</option>
    </select>
</div>

With JS:

function myCtrl ($scope) {
    $scope.units = [
        {'id': 10, 'label': 'test1'},
        {'id': 27, 'label': 'test2'},
        {'id': 39, 'label': 'test3'},
    ]

        $scope.data = {
        'id': 1,
        'unit': 27
        }

};

Answer 1

You can use the ng-selected directive on the option elements. It takes expression that if truthy will set the selected property.

In this case:

<option ng-selected="data.unit == item.id" 
        ng-repeat="item in units" 
        ng-value="item.id">{{item.label}}</option>

Demo

 angular.module("app",[]).controller("myCtrl",function($scope) { $scope.units = [ {'id': 10, 'label': 'test1'}, {'id': 27, 'label': 'test2'}, {'id': 39, 'label': 'test3'}, ] $scope.data = { 'id': 1, 'unit': 27 } }); 

 <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script> <div ng-app="app" ng-controller="myCtrl"> <select class="form-control" ng-change="unitChanged()" ng-model="data.unit"> <option ng-selected="data.unit == item.id" ng-repeat="item in units" ng-value="item.id">{{item.label}}</option> </select> </div> 

Answer 2

try the following code :

In your controller :

 function myCtrl ($scope) {
      $scope.units = [
         {'id': 10, 'label': 'test1'},
         {'id': 27, 'label': 'test2'},
         {'id': 39, 'label': 'test3'},
      ];

   $scope.data= $scope.units[0]; // Set by default the value "test1"
 };

In your page :

 <select ng-model="data" ng-options="opt as opt.label for opt in units ">
                </select>

Working Fiddle

Answer 3

您不需要定义选项标记，您可以使用ngOptions指令执行此操作： https ：//docs.angularjs.org/api/ng/directive/ngOptions

<select class="form-control" ng-change="unitChanged()" ng-model="data.unit" ng-options="unit.id as unit.label for unit in units"></select>

Answer 4

However, ngOptions provides some benefits such as reducing memory and increasing speed by not creating a new scope for each repeated instance. angular docs

Alternative solution is use ng-init directive. You can specify function that will be initialize your default data.

$scope.init = function(){
            angular.forEach($scope.units, function(item){
                if(item.id === $scope.data.unit){
                    $scope.data.unit = item;
                }
            });
        } 

See jsfiddle

Answer 5

You can also put the item with the default value selected out of the ng-repeat like follow :

<div ng-app="app" ng-controller="myCtrl">
    <select class="form-control" ng-change="unitChanged()" ng-model="data.unit">
        <option value="yourDefaultValue">Default one</option>
        <option ng-selected="data.unit == item.id" ng-repeat="item in units" ng-value="item.id">{{item.label}}</option>
    </select>
</div>

and don't forget the value atribute if you leave it blank you will have the same issue.

Answer 6

Select's default value should be one of its value in the list. In order to load the select with default value you can use ng-options . A scope variable need to be set in the controller and that variable is assigned as ng-model in HTML's select tag.

View this plunker for any references:

http://embed.plnkr.co/hQiYqaQXrtpxQ96gcZhq/preview