下拉值不与关联数组绑定

Question

我有一个像下面的关联数组，我想用我的下拉列表绑定：

{
        "Item1": [
          {
            "title": "Item1",
            "choices": [
              "Egg",
              "burger",
            ]
          }
        ],
        "Item2": [
          {
            "title": "Item2",
            "choices": [
              "Pizza",
              "Rice",
            ]
          }
        ]
     }

我正在尝试基于此关联数组绑定下拉列表，但问题是它显示为object object。

我想在下拉列表中显示每个项目的标题：

Item1
Item2

我试图从下面的SO问题中引用，但它没有成功：

key-value pairs in ng-options

Angularjs ng-options with an array of key-pair

var app = angular.module("myApp", []);
app.controller("MyController", function ($scope) {
    $scope.item=
    {
        "Item1": [
          {
            "title": "Item1",
            "choices": [
              "Egg",
              "burger",
            ]
          }
        ],
        "Item2": [
          {
            "title": "Item2",
            "choices": [
              "Pizza",
              "Rice",
            ]
          }
        ]
     }

 });

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
 <ul ng-app="myApp" ng-controller="MyController">
     <select ng-model="myItem.title" ng-options="key as value for (key , value) in item">
           <option value="">Select Items</option>
     </select>
</ul>

Answer 1

应该是这样的：

   ng-options="value as key for (key , value) in item">

var app = angular.module("myApp", []);
app.controller("MyController", function ($scope) {

    $scope.item=
    {
        "Item1": [
          {
            "title": "Item1",
            "choices": [
              "Egg",
              "burger",
            ]
          }
        ],
        "Item2": [
          {
            "title": "Item2",
            "choices": [
              "Pizza",
              "Rice",
            ]
          }
        ]
     }

 });

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
 <ul ng-app="myApp" ng-controller="MyController">
     <select ng-model="myItem.title" ng-options="value as key for (key , value) in item">
           <option value="">Select Items</option>
     </select>
     
     {{myItem.title}}
</ul>