选择AngularJs - ng模型

Problem:

问题:

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.

我的页面中有一个SELECT-element，其中填充了一个ng-repeat。它还拥有一个具有默认值的ng模型。

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.

当我改变值时，ng-model就会适应，没关系。但下拉列表显示了启动时的一个空槽，其中应该选择具有默认值的项。

Code

代码

<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:

JS:

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

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

};

6 个解决方案

#1

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

您可以在选项元素上使用ng选择的指令。如果truthy将设置所选属性，则需要表达式。

In this case:

在这种情况下:

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

Demo

演示

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>

#2

try the following code :

试试下面的代码:

In your controller :

在你的控制器:

 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 :

在你的页面:

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

Working Fiddle

工作小提琴

#3

You dont need to define option tags, you can do this using the ngOptions directive: https://docs.angularjs.org/api/ng/directive/ngOptions

不需要定义选项标签，可以使用ngOptions指令:https://docs.angularjs.org/api/ng/directive/ngOptions来实现

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

#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

但是，ngOptions提供了一些好处，比如通过不为每个重复实例创建新范围来减少内存和提高速度。角文档

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

替代解决方案是使用ng-init指令。您可以指定将初始化您的默认数据的函数。

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

See jsfiddle

看到jsfiddle

#5

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

您还可以将默认值从ng-repeat中选择的项放入如下:

<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.

不要忘记value atribute如果你把它留空，你也会遇到同样的问题。

#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.

Select的默认值应该是列表中它的值之一。为了使用默认值加载select，可以使用ng选项。需要在控制器中设置一个范围变量，该变量在HTML的select标记中被分配为ng-model。

View this plunker for any references:

查看此柱塞是否有参考:

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

#1