ngRepeat:尝试从数据库获取时出现重复

Question

无论我尝试什么，我都会不断收到提到的错误。当我注释掉课程.js文件中的"fetchCourses(("时，错误停止。我猜错误在 http 请求中的某个地方，但我无法弄清楚。

这是我的代码片段。

课程.js(控制器(

var app = angular.module("app");
app.controller('coursesCtrl', ['$scope', 'Courses', '$routeParams', function ($scope, Courses, $routeParams) {
function fetchCourses() {
Courses.getCourses({}).then(function (res) {
$scope.courses = res.data;
}, function (err) {
console.log(err);
});
}
fetchCourses();
$scope.modal = {
title: "Modal",
btnText: "Ok",
save: function () {
if ($scope.modal.type == 'course_delete') {
Courses.deleteCourse($scope.modal.req).then(function (res) {
if (res.status == 200) {
$scope.courses.splice($scope.modal.req.index, 1);
$("#course_modal").modal("hide");
}
}, function (err) {
console.log(err);
});
} else if ($scope.modal.type == 'course_create') {
Courses.createCourse($scope.modal.req).then(function (res) {
$scope.courses.unshift(res.data);
$("#course_modal").modal("hide");
}, function (err) {
console.log(err);
});
} else if ($scope.modal.type == 'course_edit') {
$scope.courses[$scope.modal.req.index] = $scope.modal.req.course;
$("#course_modal").modal("hide");
$scope.modal.req.course = null;
}
},
type: "default",
req: {},
};
$scope.createCourse = function () {
$("#course_modal").modal("show");
$scope.modal.title = "Create course";
$scope.modal.btnText = "Create";
$scope.modal.type = "course_create";
$scope.modal.req = {};
};
$scope.editCourse = function (index) {
$("#course_modal").modal("show");
$scope.modal.title = "Edit course";
$scope.modal.btnText = "Ok";
$scope.modal.type = "course_edit";
$scope.modal.req.index = index;
};
$scope.deleteCourse = function (index) {
$("#course_modal").modal("show");
$scope.modal.title = "Delete course";
$scope.modal.btnText = "Yes";
$scope.modal.type = "course_delete";
$scope.modal.req.index = index;
};

}]);

路线.js

var Students = require('../../models/students');
var Courses = require('../../models/courses');
var Departments = require('../../models/departments');
var Exams = require('../../models/exams');
var ObjectId = require('mongoose').Types.ObjectId;
var bodyParser = require('body-parser');

module.exports = function (app) {
app.use(bodyParser.urlencoded({
extended: true
}));

app.post('/getCourses', (req, res) => {
Courses.find({}).exec(function (err, documents) {
res.send(documents);
console.log(documents);
});
});


app.post('/createCourse', (req, res) => {
var data = {
coursesName: req.body.coursesName,
coursesProfessor: req.body.coursesProfessor,
coursesDepartment: req.body.coursesDepartment,
coursesNumStudents: req.body.coursesNumStudents,
};
Courses.create(data, function (err, document) {
if (err) return res.status(500).send({
message: "Sorry! There was a problem creating a course."
});
res.send(document);
console.log(document);
});
});
};

菜单.js(又名标题(

var menu = angular.module("menu", []);

menu.controller('menuCtrl', ['$scope', '$location', function ($scope, $location) {
/*
if (notloggedin){
window.location.replace("/");
} 
*/

$scope.logout = function () {
window.location.replace("/");
}
$scope.url = $location.url();
console.log($location.url());


}]);
menu.service('Courses', ['$http', function ($http) {
var Headers = {
'Content-Type': 'application/x-www-form-urlencoded',
}
var transformReq = function (obj) {
var str = [];
for (var p in obj)
str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
return str.join("&");
}
this.getCourses = function (req) {
return $http({
method: 'POST',
url: '/getCourses',
headers: Headers,
transformRequest: transformReq,
data: req
});
}
this.createCourse = function (req) {
return $http({
method: 'POST',
url: '/createCourse',
headers: Headers,
transformRequest: transformReq,
data: req
});
}
}]);

还有课程.html

<div class="wrapper">
<div ng-include="'header/menu.html'"></div>
<div class="main-panel">
<nav class="navbar navbar-default">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar bar1"></span>
<span class="icon-bar bar2"></span>
<span class="icon-bar bar3"></span>
</button>
<a class="navbar-brand" href="#">Courses</a>
</div>
</div>
</nav>

<div class="content">
<div class="container-fluid">
<div class="row">
<div class="col-md-12">
<div class="card">
<div class="header">
<h4 class="title">Courses List</h4>
<p class="category">Here is a list of all courses</p>
<button class="btn btn-success" style="float:right" ng-click="createCourse()">Create Course</button>
</div>
<div class="content table-responsive table-full-width">
<table class="table table-striped">
<thead>
<th>Name</th>
<th>Professor</th>
<th>Department</th>
<th>Num of Students</th>
<th>#</th>
</thead>
<tbody>
<tr ng-repeat="c in courses">
<td>{{c.coursesName}}</td>
<td>{{c.coursesProfessor}}</td>
<td>{{c.coursesDepartment}}</td>
<td>{{c.coursesNumStudents}}</td>
<td>
<a href="" ng-click="editCourse($index)">Edit
</a> /
<a href="" ng-click="deleteCourse($index)">Delete
</a>
</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="modal fade" id="course_modal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">&times;</button>
<h5 class="modal-title" id="modalLabel">{{modal.title}}</h5>
</div>
<div class="modal-body">
<div class="row">
<div class="col">
<form ng-if="modal.type == 'course_create' || modal.type == 'course_edit'">
<div class="form-group">
<label for="coursesName">Name</label>
<input type="text" class="form-control" ng-model="modal.req.course.coursesName" ng-disabled>
</div>
<div class="form-group">
<label for="coursesProfessor">Professor</label>
<input type="text" class="form-control" ng-model="modal.req.course.coursesProfessor" ng-disabled>
</div>
<div class="form-group">
<label for="coursesDepartment">Department</label>
<input type="text" class="form-control" ng-model="modal.req.course.coursesDepartment" ng-disabled>
</div>
<div class="form-group">
<label for="coursesNumStudents">Number of Students</label>
<input type="text" class="form-control" ng-model="modal.req.course.coursesNumStudents" ng-disabled>
</div>
</form>
<div ng-if="modal.type == 'course_delete'">
Are you sure you want to delete this course?
</div>
</div>
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-success" ng-click="modal.save()">{{modal.btnText}}</button>
</div>
</div>
</div>
</div>

Answer 1

这意味着$scope.courses有一些重复的值。重复键被禁止，因为 AngularJS 使用键将 DOM 节点与项目相关联。

因此，在这种情况下，您可以使用跟踪$index因此重复的项目将按其索引进行跟踪。

<tr ng-repeat="c in courses track by $index">{{value}}</tr>