javascript - ng-options指令不起作用，无法在angularjs库中找到它

我的ng-option指令不起作用，在AngularJS库中找不到。我尝试了几乎所有有效的来源，但仍然只有此指令不起作用。甚至我也尝试过angularjs.org网站上的代码。

<html>
<head>
    <title>View</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src= "https://ajax.googleapis.com/ajax/libs/angularjs/1.4.2/angular.min.js"></script>

    <script>
        var mymodule = angular.module('mymodule' ,[]);
        mymodule.controller('x' , function($scope){
            $scope.point = ['point1' , 'point2' , 'point3' , 'point4'];
            $scope.selectedpoint = $scope.point[1];
        });
    </script>
</head>
<body ng-app="mymodule">
    <div ng-controller="x">
        <select ng-model="selectedpoint" ng-options="item from items in point"></select>
        Select = {{selectedpoint}}
        <hr/>
        <div ng-switch="selectedpoint">
            <div style="border: 1px solid;" ng-switch-when="point1"> First file is selected</div>
            <div style="border: 1px solid;" ng-switch-when="point2"> Second file is selected</div>
            <div style="border: 1px solid;" ng-switch-when="point3"> Third file is selected</div>
            <div style="border: 1px solid;" ng-switch-when="point4"> Fourth file is selected</div>
        </div>
    </div>
</body>

最佳答案

我已经修改了代码，您使用的是“ from”而不是“ for”
Correct Verion of Code in Plunker

<html>
    <head>
        <title>View</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <script src= "https://ajax.googleapis.com/ajax/libs/angularjs/1.4.2/angular.min.js"></script>

        <script>
            var mymodule = angular.module('mymodule' ,[]);
            mymodule.controller('x' , function($scope){
                $scope.point = ['point1' , 'point2' , 'point3' , 'point4'];
                $scope.selectedpoint = $scope.point[1];
            });
        </script>
    </head>
    <body ng-app="mymodule">
        <div ng-controller="x">
            <select ng-model="selectedpoint" ng-options="item for item in point"></select>
            Select = {{selectedpoint}}
            <hr/>
            <div ng-switch="selectedpoint">
                <div style="border: 1px solid;" ng-switch-when="point1"> First file is selected</div>
                <div style="border: 1px solid;" ng-switch-when="point2"> Second file is selected</div>
                <div style="border: 1px solid;" ng-switch-when="point3"> Third file is selected</div>
                <div style="border: 1px solid;" ng-switch-when="point4"> Fourth file is selected</div>
            </div>
        </div>
    </body>
    </html>