如何在 AngularJS 中设置动态模型名称？

我想用一些动态问题填充一个表单(小提琴 给你) :

<div ng-app ng-controller="QuestionController">
<ul ng-repeat="question in Questions">
<li>
<div>{{question.Text}}</div>
<select ng-model="Answers['{{question.Name}}']" ng-options="option for option in question.Options">
</select>
</li>
</ul>


<a ng-click="ShowAnswers()">Submit</a>
</div>
​
function QuestionController($scope) {
$scope.Answers = {};


$scope.Questions = [
{
"Text": "Gender?",
"Name": "GenderQuestion",
"Options": ["Male", "Female"]},
{
"Text": "Favorite color?",
"Name": "ColorQuestion",
"Options": ["Red", "Blue", "Green"]}
];


$scope.ShowAnswers = function()
{
alert($scope.Answers["GenderQuestion"]);
alert($scope.Answers["{{question.Name}}"]);
};
}​

一切工作，除了模型是字面上的答案[“{{问题。[名称}”] ，而不是求值的答案[“性别问题”]。如何动态设置模型名称？

121099 次浏览
小开
最佳答案

http://jsfiddle.net/DrQ77/

You can simply put javascript expression in ng-model.

小开

What I ended up doing is something like this:

In the controller:

link: function($scope, $element, $attr) {
$scope.scope = $scope;  // or $scope.$parent, as needed
$scope.field = $attr.field = '_suffix';
$scope.subfield = $attr.sub_node;
...

so in the templates I could use totally dynamic names, and not just under a certain hard-coded element (like in your "Answers" case):

<textarea ng-model="scope[field][subfield]"></textarea>

Hope this helps.

小开

To make the answer provided by @abourget more complete, the value of scopeValue[field] in the following line of code could be undefined. This would result in an error when setting subfield:

<textarea ng-model="scopeValue[field][subfield]"></textarea>

One way of solving this problem is by adding an attribute ng-focus="nullSafe(field)", so your code would look like the below:

<textarea ng-focus="nullSafe(field)" ng-model="scopeValue[field][subfield]"></textarea>

Then you define nullSafe( field ) in a controller like the below:

$scope.nullSafe = function ( field ) {
if ( !$scope.scopeValue[field] ) {
$scope.scopeValue[field] = {};
}
};

This would guarantee that scopeValue[field] is not undefined before setting any value to scopeValue[field][subfield].

Note: You can't use ng-change="nullSafe(field)" to achieve the same result because ng-change happens after the ng-model has been changed, which would throw an error if scopeValue[field] is undefined.

小开

You can use something like this scopeValue[field], but if your field is in another object you will need another solution.

To solve all kind of situations, you can use this directive:

this.app.directive('dynamicModel', ['$compile', '$parse', function ($compile, $parse) {
return {
restrict: 'A',
terminal: true,
priority: 100000,
link: function (scope, elem) {
var name = $parse(elem.attr('dynamic-model'))(scope);
elem.removeAttr('dynamic-model');
elem.attr('ng-model', name);
$compile(elem)(scope);
}
};
}]);

Html example:

<input dynamic-model="'scopeValue.' + field" type="text">
小开

Or you can use

<select [(ngModel)]="Answers[''+question.Name+'']" ng-options="option for option in question.Options">
</select>

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