在 Angular JS 控制器和服务之间传递值 [英] Pass value in-between angular JS controller and services

问题描述

我正在尝试使用 ng-click 从 html 获取用户查询.我想使用从 ng-click 中获取的值进行 https 调用.我可以在 Alert--1 中看到数据，但在 Alert--2 中我得到 undefined.在互联网上，我读到使用服务传递值是最佳做法.如果我错了，请纠正我.

I am trying to get the user query from html using ng-click. I want to make a https call using the value which I fetch from ng-click. I can see the data in Alert--1 but in Alert--2 i get undefined. on internet I read that passing values using services is the best practice.Please correct me if I am wrong.

我的控制器

mainApp.controller('searchController',function($scope,searchString){

  $scope.getQuery = function(userq)  // its ng-click="getQuery(userq)" on Search button
  {
    $scope.userq=userq;
    alert('Alert--1'+userq);  // its working fine
    searchString.setSearchString(userq);
  };
});

//====================

mainApp.controller('fetchQueryResultController',function($scope,searchString){
   var searchStr = searchString.getSearchString();
   alert('Alert--2--'+searchStr);   //   Undefined
  // Later I'll use this value to fetch data from Watson search(Django) using $https call
});

我的服务:

mainApp.factory('searchString', function () {
    var qVal ;

    return {
        setSearchString:function (query) {
            qVal = query;
        },
        getSearchString:function () {
            return qVal;
        }
    };
});

路由:

.when('/search', {
     templateUrl: "../static/views/seachResult.html",
     controller: "fetchQueryResultController"
  })

有没有更简单的方法?

推荐答案

使用服务是可以的.看看这个，对于初学者来说很清楚:

Using a service is OK. Take a look at this, is quite clear for begginers:

https://egghead.io/lessons/angularjs-sharing-data-控制器间

alert('Alert--2'+searchStr); 显示未定义，因为它显然在 $scope.getQuery 之前执行.控制器的初始化在 ng-init 计算表达式之前完成.

alert('Alert--2'+searchStr); is showing undefined because it is being executed before $scope.getQuery obviously. Controller's initialization is done before ng-init evaluates the expression.

在您的情况下，我认为最好在设置数据时触发事件，以便通知第二个控制器.这是通过 $on 和 $emit 完成的.

In your case I believe it is better to fire an event when the data is set, so the second controller gets notified. This is being done with $on and $emit.

这是一个 plunker 的例子:http://plnkr.co/edit/97mVwbWmoOH3F7m8wbN0?p=预览

Here is a plunker with your example: http://plnkr.co/edit/97mVwbWmoOH3F7m8wbN0?p=preview

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

app.controller('searchController',function($scope,searchString){

  $scope.searchText;

  $scope.getQuery = function(userq)  // its ng-click="getQuery(userq)" on Search button
  {
    $scope.userq=userq;
    alert('Alert--1'+userq);  // its working fine
    searchString.setSearchString(userq, $scope);
  };
});

//====================

app.controller('fetchQueryResultController',function($scope, $rootScope, searchString){
   var searchStr = searchString.getSearchString;

   $scope.getData = function(){
     searchStr = searchString.getSearchString();
     alert('Alert--2--'+ searchStr); 
   }

   $rootScope.$on('dataModified', function(){
     $scope.getData();
   });

});

//====================

app.factory('searchString', function ($rootScope) {
    var qVal ;

    return {
        setSearchString:function (query) {
            qVal = query;
            $rootScope.$emit('dataModified');
        },
        getSearchString:function () {
            return qVal;
        }
    };
});

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