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我对 Angular 很陌生，并试图实现一些“基本”的东西。我已经在谷歌上搜索了 2 天但没有成功，希望能得到一些帮助。

我有一个 html 页面，我正在尝试：

  1. 使用 HTTP POST 请求初始化数据
  2. 当用作过滤器的元素发生更改（即类别、按 asc/desc 排序...）时，通过 ng-change 事件调用函数以使用另一个 HTTP POST 更新数据

我的问题是，当我使用 HTTP 响应（仅在这种情况下）以编程方式更新模型时，它会触发附加到元素的 ng-change 事件，该事件本身会调用更新函数，然后进入无限循环：ng -change -> 更新函数 -> ng-change -> 更新函数

注意：我正在使用 Angular Material 模板，但它不会更改代码

HTML

<html ng-app="MyApp">
    <body layout="column" ng-controller="SearchServiceController">
        <h1 class="md-headline">Filter results</h1>
        <form name="searchServiceForm" novalidate>
            <md-input-container>
                <md-select placeholder="Choose category" ng-model="searchService.selectedCategory" ng-change="changedSearchServiceCriteria()">
                    <md-option ng-value="category.value" ng-repeat="category in listOfCategories">{{ category.title }}</md-option>
                </md-select>
             </md-input-container>
             <md-input-container>
                 <md-select placeholder="Sort by" ng-model="searchService.sortBy" ng-change="changedSearchServiceCriteria()">
                     <md-option ng-value="criteria.value" ng-repeat="criteria in sortByCriterias">{{ criteria.title }}</md-option>
                  </md-select>
              </md-input-container>
          </form>
          <h1 class="md-headline">{{ selectedCategory.title }}</h1>
          <p class="md-body-1">{{ selectedCategory.description }}</p>
    </body>
</html>

JS

var app = angular.module('MyApp', ['ngMaterial']);

app.controller('SearchServiceController', function($scope, $http, $location) {
  // Initialize data using the category id parameter in the URL
  $http({
    method: 'POST',
    url: '/projets/get-offerings-list',
    data: {selectedCategory: $location.path().split("/")[4]},
    headers: {'Content-Type': 'application/x-www-form-urlencoded'}
    })
      .success(function(response) {
        alert('INIT');
        $scope.listOfCategories = response.listOfCategories;
        $scope.sortByCriterias = response.sortByCriterias;
        $scope.searchService = response.searchService;
      })
      .error(function(response) {
        console.log('Failure occured');
      });

  // Update data
  $scope.changedSearchServiceCriteria = function() {
    $http({
    method: 'POST',
    url: '/projets/get-offerings-list',
    data: {selectedCategory: $location.path().split("/")[4]},
    headers: {'Content-Type': 'application/x-www-form-urlencoded'}
    })
      .success(function(response) {
        alert('UPDATE');
        $scope.listOfCategories = response.listOfCategories;
        $scope.sortByCriterias = response.sortByCriterias;
        $scope.searchService = response.searchService;
      })
      .error(function(response) {
        console.log('Failure occured');
      });
  };
});

结果

INIT
Object {listOfCategories: Array[3], sortByCriterias: Array[2], searchService: Object}
UPDATE
Object {listOfCategories: Array[3], sortByCriterias: Array[2], searchService: Object}
UPDATE
Object {listOfCategories: Array[3], sortByCriterias: Array[2], searchService: Object}
UPDATE
Object {listOfCategories: Array[3], sortByCriterias: Array[2], searchService: Object}
UPDATE
Object {listOfCategories: Array[3], sortByCriterias: Array[2], searchService: Object}
UPDATE
Object {listOfCategories: Array[3], sortByCriterias: Array[2], searchService: Object}
....infinite loop....

当我以编程方式更新模型而不使用 HTTP 请求的响应时，不会发生这种情况。请参见此处：http ://plnkr.co/edit/baNjr85eAOkKVu4dnf1m?p= preview 您对如何在不引发 ng-change 事件的情况下更新表单元素有任何想法吗？

谢谢

请注意，我不想像那里那样使用 $watch 的解决方法：ngChange is called when model changed in programmatically

4

1 回答 1

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您应该尝试将一个工作示例添加到http://jsfiddle.net/或类似文件中。

我会认为是猜测而不是测试你需要保留最后一次搜索并且只运行更新 AJAX 请求，如果它每次都获得一个新地址（或 JS 中调用的任何内容）而发生变化 - 即使它的值相同并重新评估

$scope.searchService = "";
$scope.lastSearch = ""

// Update data using form elements
$scope.changedSearch = function() {

    if($scope.searchService != $scope.lastSearch){

      $http({
        method: 'POST',
        url: '/projects/get-list',
        data: $scope.searchService,
        headers: {'Content-Type': 'application/x-www-form-urlencoded'}
      })
        .success(function(response) {
            // Request succeeded? Display message
            console.log('UPDATE');
            console.log(response);
            // Update data
            $scope.listOfCategories = response.listOfCategories;
            $scope.sortByCriterias = response.sortByCriterias;
            $scope.searchForm = response.searchForm;
        })
          .error(function(response) {
            // Request failed? Display message
            console.log('Failure occured');
        })
          .complete(function(response) {
            // do after success or error
            $scope.lastSearch = $scope.searchService;
            console.log('complete');
        });
    }
};
于 2015-07-16T21:14:19.487 回答