前端使用AngularJS的$resource,后端ASP.NET Web API，实现增删改查

AngularJS中的$resource服务相比$http服务更适合与RESTful服务进行交互。本篇后端使用ASP.NET Web API, 前端使用$resource，实现增删改查。

本系列包括：

1、前端使用AngularJS的$resource,后端ASP.NET Web API，实现增删改查
2、前端使用AngularJS的$resource,后端ASP.NET Web API，实现分页、过滤

领域和上下文

首先领域先行。

    public class StudentVm
    {
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }
        public string Age { get; set; }
    }

上下文。

        public class StudentContext : DbContext
        {
            public StudentContext() : base("conn")
            {
                Database.SetInitializer(new StudentInitializer());
            }
 
            public DbSet<StudentVm> Students { get; set; }
        }

上下文的构造函数中，StudentIntializer类对数据进行了初始化。

    public class StudentInitializer : CreateDatabaseIfNotExists<StudentContext>
    {
        protected override void Seed(StudentContext context)
        {
            IList<StudentVm> students = new List<StudentVm>();
            students.Add(new StudentVm() { Name = "aa", Age = "" });
            students.Add(new StudentVm() { Name = "bb", Age = "" });
            students.Add(new StudentVm() { Name = "cc", Age = "" });
            students.Add(new StudentVm() { Name = "dd", Age = "" });
            students.Add(new StudentVm() { Name = "ee", Age = "" });
            students.Add(new StudentVm() { Name = "ff", Age = "" });
            students.Add(new StudentVm() { Name = "gg", Age = "" });
 
            foreach(StudentVm student in students)
            {
                context.Students.Add(student);
            }
 
            base.Seed(context);
        }
    }

对于EF Code First来说，Web.config中需要配置连接字符串。

  <connectionStrings>
    <add name="conn"
       connectionString="Data Source=.;User=yourname;Password=yourpassword;Initial Catalog=StudentsDemo;Integrated Security=True"
       providerName="System.Data.SqlClient"/>
  </connectionStrings>

Repository

在这里使用上下文类，实现增删改查。

    public class StudentsReop
    {
        private StudentContext _db = new StudentContext();
 
        public IEnumerable<StudentVm> Query()
        {
            return _db.Students;
        }
 
        public StudentVm Get(int id)
        {
            return _db.Students.SingleOrDefault(s => s.Id == id);
        }
 
        //更新
        public void Put(int id, StudentVm student)
        {
            var stu = _db.Students.SingleOrDefault(s => s.Id == id);
            _db.Students.Attach(stu);
            _db.Entry(stu).State = System.Data.Entity.EntityState.Modified;
            _db.Entry(stu).CurrentValues.SetValues(student);
            _db.SaveChanges();
        }
 
        //添加
        public void Post(StudentVm student)
        {
            _db.Students.Add(student);
            _db.SaveChanges();
        }
 
        public void Delete(int id)
        {
            var student = _db.Students.SingleOrDefault(s => s.Id.Equals(id));
            _db.Students.Remove(student);
            bool saveFailed;
            do
            {
                saveFailed = false;
 
                try
                {
                    _db.SaveChanges();
                }
                catch (DbUpdateConcurrencyException ex)
                {
                    saveFailed = true;
 
                    //重新加载数据库中的实体，使之处于unchanged的状态
                    ex.Entries.Single().Reload();
                }
            } while (saveFailed);
        }
    }

API控制器

   public class StudentsController : ApiController
    {
        private StudentsReop _reop = new StudentsReop();
 
        //GET api/Students
        public HttpResponseMessage Get()
        {
            var students = _reop.Query().ToList();
            return Request.CreateResponse(HttpStatusCode.OK, students);
        }
 
        //GET api/Students/5
        public HttpResponseMessage Get(int id)
        {
            var student = _reop.Get(id);
            return Request.CreateResponse(HttpStatusCode.OK, student);
        }
 
        //POST api/Students
        public void Post([FromBody]StudentVm student)
        {
            _reop.Post(student);
        }
 
        //PUT api/Students/5
        public void Put(int id, [FromBody]StudentVm student)
        {
            _reop.Put(id, student);
        }
 
        //DELETE api/Students
        public void Delete(int id)
        {
            _reop.Delete(id);
        }
    }

允许跨域访问

默认情况下，ASP.NET Web API是不支持跨域访问的。为了支持，需要安装Microsoft.AspNet.WebApi.Cors。安装之后，需要在全局配置生效。在WepApiConfig.cs中配置如下：

    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API 配置和服务
 
            // Web API 路由
            config.MapHttpAttributeRoutes();
 
            config.EnableCors(new EnableCorsAttribute("*", "*", "*"));
 
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
        }
    }

在本地，浏览器中：http://localhost:49621/api/Students

前端准备

后端完成，前端在WebStorm下安装先安装需要的几个插件：

npm install angular
npm install angular-route
npm install angular-resource
npm install angular-cookies
npm install alertify
 
再来了解下前端的文件结构：
 
app.js 主module，路由都在这里配置
index.html 主视图，引用所有的css,js文件，提供让其它部分视图呈现的一块区域<div ng-view></div>
.....service/ 自定义服务，$resouce的核心就封装在这里
..........studentService.js
.....controller/
..........studentsCtrl.js 列表
..........studentUpdateCtrl.js 更新
..........studentCreateCtrl.js 添加
.....views/
..........Students.html 列表
..........StudentInfo.html 更新
..........StudentCreate.html 添加
 

index.html

<!DOCTYPE html>
<html lang="en" ng-app="studentManagement">
<head>
  <meta charset="UTF-8">
  <title>{{title}}</title>
  <link rel="stylesheet" href="node_modules/alertify/themes/alertify.core.css"/>
</head>
<body>
  <div>
    <p>
      <a href="#/">Students</a>
      &nbsp;&nbsp;
      <a href="#/Create">Create Student</a>
    </p>
  </div>
 
  <div ng-view></div>
 
  <script src="node_modules/angular/angular.min.js"></script>
  <script src="node_modules/angular-route/angular-route.min.js"></script>
  <script src="node_modules/angular-resource/angular-resource.min.js"></script>
  <script src="node_modules/angular-cookies/angular-cookies.min.js"></script>
  <script src="node_modules/alertify/lib/alertify.min.js"></script>
 
  <script src="app.js"></script>
 
  <script src="service/studentService.js"></script>
  <script src="controller/studentUpdateCtrl.js"></script>
  <script src="controller/studentsCtrl.js"></script>
  <script src="controller/studentCreateCtrl.js"></script>
 
</body>
</html>

以上，主视图中，需要注意引用js文件的顺序，一般angualr相关方在最上面，然后app对应js文件，最后是各种服务和控制器相关js文件。

app.js

在这里，当然首先要定义一个module，定义module的时候要把所有用到的module依赖写在module方法的第二个实参里。还有一个主项工作就是定义设置路由，而且，如果想让以后视同从controller中拿数据更快，我们还可以利用路由的resolve机制，把数据从某处读取出来，先放到路由中，然后在controller中把resolve机制下的数据读出来。

"use strict";
 
var studentsManagement = angular.module("studentManagement",["ngResource","ngCookies","ngRoute"])
    .run(function($rootScope){
        $rootScope.title = "Home";
    })
    .config(["$routeProvider","$locationProvider", function($routeProvider, $locationProvider){
 
        //关于url的基本配置
        //$locationProvider.html5Mode({
        //    enabled: true,
        //    requireBase: false
        //});
 
        //配置路由
        $routeProvider.when("/", {
            templateUrl: "views/Students.html",
            controller: "studentsCtrl",
            resolve: {
                students: function($q,studentDataService){
 
                    //$q异步执行方法
                    var deferred = $q.defer();
                    studentDataService.query(function(data){
                        deferred.resolve(data);
                    });
 
                    return deferred.promise;
                }
            }
        }).when("/Student/:id",{
            templateUrl: "views/StudentInfo.html",
            controller: "studentUpdateCtrl",
            resolve: {
                student: function($q, studentDataService, $route){
                    var defered = $q.defer();
 
                    //从路由中获取id的值
                    var id = $route.current.params.id;
 
                    studentDataService.get({id: id}, function(data){
                        defered.resolve(data);
                    });
 
                    return defered.promise;
                }
            }
        }).when("/Create",{
            templateUrl: "views/CreateStudent.html",
            controller: "studentCreateCtrl"
        });
 
    }]);

● 使用$routeProvider配置路由的过程就是让一对对view和controller结婚的过程

● 显示列表的时候通过路由的resolve机制把数据先放在了路由中

● 显示某个Sudent的时候也通过路由的resolve机制把数据先放在了路由中

●/Student/:id这个路由格式中的id代表变量，可借助$route服务从路由中取出来var id = $route.current.params.id;

studentService.js

在这里，封装了对API的所有请求。

而$resource服务是位于angular-resource中，大致按如下调用：

$resource(url,{paramDefaults},{actions},{options});

其中，第一个参数是必须的，其它都optional。

angular.module('studentManagement').factory("studentDataService",["$resource", function($resource){
 
    var baseUrl = "http://localhost:49621/api/Students";
    return $resource("http://localhost:49621/api/Students",{},{
        query: {method: "GET", isArray: true },
        create: {method: "POST"},
        get: {method: "GET", url: baseUrl + "?id=:id"},
        remove: {method: "DELETE", url: baseUrl + "?id=:id"},
        update: {method: "PUT", url: baseUrl + "?id=:id"}
    })
}]);

以上，在"?id=:id"中，冒号后面的id是一个变量，在controller中通过对象传递到这里来，比如 studentDataService.remove({id: id}).$promise.then(...)

列表，studentsCtr.j和views/Students.html这对恋人

studentsCtr.js：

angular.module('studentManagement').controller("studentsCtrl",['$scope','$route','$rootScope','studentDataService', function($scope,$route, $rootScope, studentDataService){
    $rootScope.title = "Students";
    $scope.students = $route.current.locals.students;//students在路由resolve中定义
    $scope.removeStudent = function(id, student){
        studentDataService.remove({id: id}).$promise.then(function(){
            //获取student在当前集合中的索引
            var index = $scope.students.indexOf(student);
            $scope.students.splice(index, 1);
            alertify.log(student.Name + ' is removed');
        });
    };
 
}]);

以上，students的数据并没有向那个源头发出请求获取，而是直接使用$route服务，把路由resolve机制中的变量值取了出来。删除数据实际是做2件事，一件是删除服务端的数据，一件是删除model中的数据。

Students.html:

<table>
  <thead>
    <tr>
      <th>Name</th><th>Age</th><th>Actions</th>
    </tr>
  </thead>
  <tbody>
    <tr ng-repeat="student in students">
      <td>{{student.Name}}</td>
      <td>{{student.Age}}</td>
      <td>
        <a href="#/Student/{{student.Id}}">更新</a>
        &nbsp;&nbsp;
        <a href="javascript:void(0)" ng-click="$parent.removeStudent(student.Id, student)">移除</a>
      </td>
    </tr>
  </tbody>
</table>

添加，studentCreateCtrl.js和views/CreateStudent.html这对恋人

studentCreateCtrl.js：

angular.module('studentManagement').controller("studentCreateCtrl", ["$scope", "studentDataService", '$rootScope', "$location", function ($scope, studentDataService, $rootScope, $location) {
    $rootScope.title = "Create student";
 
    $scope.saveStudent = function (student) {
        studentDataService.create(student).$promise.then(function (res) {
            $location.path('/');
        });
    };
}]);

CreateStudent.html：

<form>
  <input id="userName" ng-model="student.Name" />
  <br/>
  <input id="userAge" ng-model="student.Age" />
  <br/>
  <button ng-click="saveStudent(student)">Save</button>
  <button type="reset">Cancel</button>
</form>

更新，studentUpdateCtrl.js和views/StudentInfo.html这对恋人

studentUpdateCtrl.js：

angular.module('studentManagement').controller("studentUpdateCtrl",["$scope","$route","$rootScope","studentDataService","$location", function($scope,$route, $rootScope, studentDataService, $location){
 
    //student是在resolve中定义的
    $scope.student = $route.current.locals.student;
    $rootScope.title = "Student Info -" + $scope.student.Name;
    $scope.updateInfo = function(student){
      studentDataService.update({id: student.Id}, student).$promise.then(function(){
          $location.url("/");
          alertify.log("Updated Student Scucess");
      });
    };
}]);

StudentInfo.html：

<form>
  <input type="text" id="userName" ng-model="student.Name"/>
  <br/>
  <input type="text" id="userAge" ng-model="student.Age"/>
  <br/>
  <button ng-click="updateInfo(student)">Update</button>
  <button type="reset">Reset</button>
</form>

待续~~