使用 angular.js 重置模型 [英] Reset a model with angular.js

问题描述

我只是尝试像这样重置值:

$scope.initial = [{数据 1: 10,数据 2:20}];$scope.datas= $scope.initial;$scope.reset = function(){$scope.datas = $scope.initial;}

但它没有产生任何东西，有什么解决办法吗?

angular.module('app', []).controller('MyCtrl', function($scope) {$scope.initial = [{数据1:10，数据 2:20}];$scope.datas= $scope.initial;$scope.reset = function(){$scope.datas = $scope.initial;}});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script><div ng-app="app" ng-controller="MyCtrl"><div ng-repeat="数据中的数据"><input type="text" ng-model="data.data1"/><input type="text" ng-model="data.data2"/>

<a ng-click="reset()">重置为初始值</a>或者<button ng-click="name = initial">重置为初始值</button><小时/><p ng-repeat="data in data">{{data.data1}}, {{data.data2}}</p>

有一个关于 jsfiddle

的工作示例

解决方案

这确实是一个关于 JavaScript 的问题(所以我添加了javascript"标签).当一个 JavaScript 对象(例如数组 $scope.initial)被分配给一个变量时，它是通过引用而不是通过复制来分配的.所以，这个声明

$scope.datas= $scope.initial;

导致 $scope.datas 指向 $scope.initial 对象.对 $scope.datas 或 $scope.initial 所做的任何更改都会影响同一个(单个)对象.由于 ng-model 用于对对象元素 data1 和 data2 进行数据绑定，因此对文本输入的任何更改都将更改 $scope.datas 引用的对象的 data1 和 data2 元素——即 $scope.initial.要查看此操作，请将以下内容添加到您的小提琴的 HTML 中:

{{initial}}

当您更改文本框中的值时，您会看到 $scope.initial 也在更改.

@Max 提供了部分答案:在重置函数中使用 angular.copy().但是，您还必须在初始分配中使用 angular.copy() :

 $scope.datas = angular.copy($scope.initial);

<小时>

更新:

正如@EpokK 在他的回答中所示，另一种解决方案是

angular.copy($scope.initial, $scope.datas);

正如@bekite 在他的回答中提到的，@EpokK 的解决方案不会创建另一个对象.

完整代码

angular.module('app', []).controller('MyCtrl', function($scope) {$scope.initial = [{数据 1: 10,数据 2:20}];$scope.datas = angular.copy($scope.initial);$scope.reset = 函数 () {$scope.datas = angular.copy($scope.initial);//或者//angular.copy($scope.initial, $scope.datas);}});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script><div ng-app="app" ng-controller="MyCtrl"><div ng-repeat="数据中的数据"><input type="text" ng-model="data.data1"/><input type="text" ng-model="data.data2"/>

<a ng-click="reset()">重置为初始值</a>或者<小时/><p ng-repeat="data in datas">{{data.data1}}, {{data.data2}}</p>{{initial}}

小提琴

I'm simply try to reset values like this :

$scope.initial = [
    {
        data1: 10,
        data2: 20
    }            
];


$scope.datas= $scope.initial;


$scope.reset = function(){
  $scope.datas = $scope.initial;  
}

But it doesn't produce anything, any idea to fix it ?

angular.module('app', []).controller('MyCtrl', function($scope) {
  $scope.initial = [
    {
      data1: 10,
      data2: 20
    }            
  ];

  $scope.datas= $scope.initial;

  $scope.reset = function(){
    $scope.datas = $scope.initial;  
  } 
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="app" ng-controller="MyCtrl">
  <div ng-repeat="data in datas">
    <input type="text" ng-model="data.data1" />
    <input type="text" ng-model="data.data2" />
  </div>
  <a ng-click="reset()">Reset to initial value</a>
  or     
  <button ng-click="name = initial">Reset to initial value</button>
  <hr />
  <p ng-repeat="data in datas">{{data.data1}}, {{data.data2}}</p>
</div>

There is a working example on jsfiddle

解决方案

This is really a question about JavaScript (so I added the "javascript" tag). When a JavaScript object (such as array $scope.initial) is assigned to a variable, it is assigned by reference, not by copy. So, this statement

$scope.datas= $scope.initial;

results in $scope.datas pointing to the $scope.initial object. Any changes that are made to $scope.datas or $scope.initial both affect the same (single) object. Since ng-model is used to data-bind object elements data1 and data2, any changes to the text inputs will change the data1 and data2 elements of the object that $scope.datas references -- i.e., $scope.initial. To see this in action, add the following to your fiddle's HTML:

<p>{{initial}}</p>

When you change the values in the text boxes, you'll see that $scope.initial is also changing.

@Max provided a partial answer: use angular.copy() in the reset function. However, you'll also have to use angular.copy() in the initial assignment too:

 $scope.datas = angular.copy($scope.initial);

---

Update:

As @EpokK shows in his answer, an alternate solution is

angular.copy($scope.initial, $scope.datas);

As @bekite mentions in his answer, @EpokK's solution does not create another object.

The full code

angular.module('app', []).controller('MyCtrl', function($scope) {
  $scope.initial = [{
    data1: 10,
    data2: 20
  }];
  $scope.datas = angular.copy($scope.initial);
  $scope.reset = function () {
    $scope.datas = angular.copy($scope.initial);
    // or
    // angular.copy($scope.initial, $scope.datas);
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>

<div ng-app="app" ng-controller="MyCtrl">
  <div ng-repeat="data in datas">
    <input type="text" ng-model="data.data1" />
    <input type="text" ng-model="data.data2" />
  </div> 
  <a ng-click="reset()">Reset to initial value</a>
  or
  <hr />
  <p ng-repeat="data in datas">{{data.data1}}, {{data.data2}}</p>{{initial}}
</div>

fiddle

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