Question

我对Angular很新，并尝试实现“基本”的东西。我一直在谷歌搜索2天没有成功，并希望得到一些帮助。

我有一个html页面，我正在尝试：

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

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 - ＆gt;更新功能 - ＆gt; ng-change - ＆gt;更新功能

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');
      });
  };
});

RESULT

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....

当我在不使用HTTP请求的响应的情况下以编程方式更新模型时，不会发生这种情况。见这里：http://plnkr.co/edit/baNjr85eAOkKVu4dnf1m?p=preview 您是否对如何在不激发ng-change事件的情况下更新表单元素有任何想法？

由于

请注意，我不想使用$ watch这样的解决方法：ngChange is called when model changed programmatically

Answer 1

您应该尝试将工作示例添加到http://jsfiddle.net/或类似内容中。

我会猜测，并且没有测试过你需要保留最后一次搜索，只有当它每次都获得一个新地址（或者在JS中调用的任何内容）发生变化时才运行更新AJAX请求 - 即使它相同的值并重新评估

$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');
        });
    }
};

使用ng-change设置$ scope.myModel元素进入无限循环

1 个答案: