MVC中使用Web API和EntityFramework

在ASP.NET MVC中使用Web API和EntityFramework构建应用程序

 

最近做了一个项目技术预研：在ASP.NET MVC框架中使用Web API和EntityFramework，构建一个基础的架构，并在此基础上实现基本的CRUD应用。

以下是详细的步骤。

第一步

在数据库中创建一张数据表，表名为Customer，见下图：

第二步

• 打开 Visual Studio，新建项目。

• 选择'ASP.NET Web Application',命名为'WebApi'。
  

• 我们要创建一个'Web API'，在模板中选择'Web API',点击'确定'。
  

  第三步

  接下来我要添加一个类。

• 右键点击这个 web api项目，添加一个'ADO.NET Entity Data Model'。
  

• 添加'EF Designer from database',点击'下一步'。
  

• 在配置窗口中添加新连接，输入服务器名称，选择数据库，点击'确定'。
  

• 点击'下一步'，选择要关联的数据表。
  

• 点击'完成'。

  第四步

  现在的工作就是要为Wep Api添加控制器了。

• 右键选择'controllers'文件夹。
  

• 选择'MVC5 Controller with views, using Entity Framework'。
  

• 点击'添加'。

• 选择数据模型类Customer，选择Data context类文件，本例中为SystemTestEntity。

• 设置控制器名称为CustomersController，点击'添加'。
  
  上述操作完成后，CustomerController.cs会自动生成。

CustomerController.cs

using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Web.Http;
using System.Web.Http.Description;
using CRUDWebApiExam.Models;  

namespace CRUDWebApiExam.Controllers
{
    public class CustomersController : ApiController
    {
        private SystemTestEntities db = new SystemTestEntities();  

        // GET: api/Customers
        public IQueryable<Customer> GetCustomer()
        {
            return db.Customer;
        }  

        // GET: api/Customers/5
        [ResponseType(typeof(Customer))]
        public IHttpActionResult GetCustomer(int id)
        {
            Customer customer = db.Customer.Find(id);
            if (customer == null)
            {
                return NotFound();
            }
            return Ok(customer);
        }  

        // PUT: api/Customers/5
        [ResponseType(typeof(void))]
        public IHttpActionResult PutCustomer(int id, Customer customer)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            if (id != customer.CustomerId)
            {
                return BadRequest();
            }
            db.Entry(customer).State = EntityState.Modified;
            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!CustomerExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }
            return StatusCode(HttpStatusCode.NoContent);
        }  

        // POST: api/Customers
        [ResponseType(typeof(Customer))]
        public IHttpActionResult PostCustomer(Customer customer)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            db.Customer.Add(customer);
            db.SaveChanges();
            return CreatedAtRoute("DefaultApi", new { id = customer.CustomerId }, customer);
        }  

        // DELETE: api/Customers/5
        [ResponseType(typeof(Customer))]
        public IHttpActionResult DeleteCustomer(int id)
        {
            Customer customer = db.Customer.Find(id);
            if (customer == null)
            {
                return NotFound();
            }
            db.Customer.Remove(customer);
            db.SaveChanges();
            return Ok(customer);
        }  

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                db.Dispose();
            }
            base.Dispose(disposing);
        }  

        private bool CustomerExists(int id)
        {
            return db.Customer.Count(e => e.CustomerId == id) > 0;
        }
    }
}  

运行这个 Web Api项目，你会看到下面的结果

第五步

到此为止，web api已经构建成功了。接下来我们需要为这个web api服务添加消费对象了，这个消费对象就是本文要涉及的MVC项目。

• 首先要添加一个model类，我们可以直接采用上文中的Customer类。右键点击models文件夹，添加类并命名。本例中，我直接命名为Customer.cs。
  Customer.cs

using System;
using System.ComponentModel.DataAnnotations;  

namespace MVCPersatantion.Models
{
    public class Customer
    {
        [Display(Name = "CustomerId")]
        public int CustomerId { get; set; }
        [Display(Name = "Name")]
        public string Name { get; set; }
        [Display(Name = "Address")]
        public string Address { get; set; }
        [Display(Name = "MobileNo")]
        public string MobileNo { get; set; }
        [Display(Name = "Birthdate")]
        [DataType(DataType.Date)]
        public DateTime Birthdate { get; set; }
        [Display(Name = "EmailId")]
        public string EmailId { get; set; }
    }
}  

• customer类添加完成后，接下来需要添加一个ViewModel文件夹，并在里面新建一个CustomerViewModel.cs文件。
  CustomerViewModel.cs

using MVCPersatantion.Models;  

namespace MVCPersatantion.ViewModel
{
    public class CustomerViewModel
    {
        public Customer customer { get; set; }
    }
}

第六步

我已经添加了一个消费web api服务的类，现在我还需要添加一个Client类。

• 右键点击models文件夹，添加类文件CustomerClient.cs。
  CustomerClient.cs

using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;  

namespace MVCPersatantion.Models
{
    public class CustomerClient
    {
        private string Base_URL = "http://localhost:30110/api/";  

        public IEnumerable<Customer> findAll()
        {
            try
            {
                HttpClient client = new HttpClient();
                client.BaseAddress = new Uri(Base_URL);
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                HttpResponseMessage response = client.GetAsync("customers").Result;  

                if (response.IsSuccessStatusCode)
                    return response.Content.ReadAsAsync<IEnumerable<Customer>>().Result;
                return null;
            }
            catch
            {
                return null;
            }
        }
        public Customer find(int id)
        {
            try
            {
                HttpClient client = new HttpClient();
                client.BaseAddress = new Uri(Base_URL);
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                HttpResponseMessage response = client.GetAsync("customers/" + id).Result;  

                if (response.IsSuccessStatusCode)
                    return response.Content.ReadAsAsync<Customer>().Result;
                return null;
            }
            catch
            {
                return null;
            }
        }
        public bool Create(Customer customer)
        {
            try
            {
                HttpClient client = new HttpClient();
                client.BaseAddress = new Uri(Base_URL);
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                HttpResponseMessage response = client.PostAsJsonAsync("customers", customer).Result;
                return response.IsSuccessStatusCode;
            }
            catch
            {
                return false;
            }
        }
        public bool Edit(Customer customer)
        {
            try
            {
                HttpClient client = new HttpClient();
                client.BaseAddress = new Uri(Base_URL);
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                HttpResponseMessage response = client.PutAsJsonAsync("customers/" + customer.CustomerId, customer).Result;
                return response.IsSuccessStatusCode;
            }
            catch
            {
                return false;
            }
        }
        public bool Delete(int id)
        {
            try
            {
                HttpClient client = new HttpClient();
                client.BaseAddress = new Uri(Base_URL);
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                HttpResponseMessage response = client.DeleteAsync("customers/" + id).Result;
                return response.IsSuccessStatusCode;
            }
            catch
            {
                return false;
            }
        }
    }
}

细心的朋友们可能已经发现，我的代码中有一些重复代码。实际应用中我们可以抽取成公用代码，这样任何地方都能够使用了。这里为了清楚的阐述过程，所以写了一些重复的代码。

我们看第一行private string Base_URL = "http://localhost:50985/api/"，这个Base_URL是web api的服务地址。

接下来就可以编写Insert、Update、Delete、Select的业务逻辑了。

第七步

右键点击Controllers文件夹，添加一个名为Customer控制器，控制器中添加服务客户端调用的方法。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MVCPersatantion.Models;
using MVCPersatantion.ViewModel;  

namespace MVCPersatantion.Controllers
{
    public class CustomerController : Controller
    {
        // GET: Customer
        public ActionResult Index()
        {
            CustomerClient CC = new CustomerClient();
            ViewBag.listCustomers = CC.findAll();
            return View();
        }
        [HttpGet]
        public ActionResult Create()
        {
            return View("Create");
        }
        [HttpPost]
        public ActionResult Create(CustomerViewModel cvm)
        {
            CustomerClient CC = new CustomerClient();
            CC.Create(cvm.customer);
            return RedirectToAction("Index");
        }  

        public ActionResult Delete(int id)
        {
            CustomerClient CC = new CustomerClient();
            CC.Delete(id);
            return RedirectToAction("Index");
        }
        [HttpGet]
        public ActionResult Edit(int id)
        {
            CustomerClient CC = new CustomerClient();
            CustomerViewModel CVM = new CustomerViewModel();
            CVM.customer = CC.find(id);
            return View("Edit",CVM);
        }
        [HttpPost]
        public ActionResult Edit(CustomerViewModel CVM)
        {
            CustomerClient CC = new CustomerClient();
            CC.Edit(CVM.customer);
            return RedirectToAction("Index");
        }
    }
}  

第八步

• 创建视图页面Index.cshtml。

• 在Index页面中添加代码。
  Index.cshtml

@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>

<div align="center">
    @Html.ActionLink("Create", "Create", "Customer", new { area = "" }, null)
    <br /><br />
    <table cellpadding="2"
           class="table"
           cellspacing="2"
           border="1">
        <tr class="btn-primary">

            <th>
                CustomerId
            </th>
            <th> Name</th>
            <th> Address</th>
            <th> MobileNo</th>
            <th> Birthdate</th>
            <th> EmailId</th>
            <th> Action</th>
        </tr>
        @foreach (var Cust in ViewBag.listCustomers)
        {
            <tr class="btn-success">
                <td>
                    @Cust.CustomerId
                </td>
                <td>
                    @Cust.Name
                </td>
                <td>
                    @Cust.Address
                </td>
                <td>
                    @Cust.MobileNo
                </td>
                <td>
                    @Cust.Birthdate.ToString("dd/MM/yyyy")
                </td>
                <td>
                    @Cust.EmailId
                </td>
                <td>
                    <a onclick="return confirm('确定要删除这条数据?')"
                       href="@Url.Action("Delete","Customer",new {id= Cust.CustomerId})">Delete</a> ||
                    <a href="@Url.Action("Edit","Customer",new {id= Cust.CustomerId})">Edit</a>
                   @*@Html.ActionLink("Edit", "Edit", "Customer", new { id = Cust.CustomerId })*@
                </td>

            </tr>
        }
    </table>
</div>

• 添加新增数据模块Create。

• 在Customer控制器中添加create方法，在view中增加Create.cshtml。

Create.cshtml

@model WebApiMVC.ViewModel.CustomerViewModel

@{
    ViewBag.Title = "Create";
}

<h2>Create</h2>

<div align = "center" >
@using (Html.BeginForm("create", "Customer", FormMethod.Post))
{
    <table class="table">
        <tr>
            <td>
                @Html.LabelFor(model => model.customer.Name)
            </td>

            <td>
                @Html.TextBoxFor(model => model.customer.Name)
            </td>
        </tr>
        <tr>
            <td>
                @Html.LabelFor(model => model.customer.Address)
            </td>

            <td>
                @Html.TextBoxFor(model => model.customer.Address)
            </td>
        </tr>
        <tr>
            <td>
                @Html.LabelFor(model => model.customer.MobileNo)
            </td>

            <td>
                @Html.TextBoxFor(model => model.customer.MobileNo)
            </td>
        </tr>
        <tr>
            <td>
                @Html.LabelFor(model => model.customer.Birthdate)
            </td>

            <td>
                @Html.TextBoxFor(model => model.customer.Birthdate)
            </td>
        </tr>
        <tr>
            <td>
                @Html.LabelFor(model => model.customer.EmailId)
            </td>

            <td>
                @Html.TextBoxFor(model => model.customer.EmailId)
            </td>
        </tr>
        <tr>
            <td></td>

            <td>
                <input type="submit"  value="保存" />
            </td>
        </tr>
    </table>
}
    </div>

• 添加修改数据模块Edit。

• 在Customer控制器中添加edit方法，在view中增加Edit.cshtml。

Edit.cshtml

@{
    ViewBag.Title = "Edit";
}

@model WebApiMVC.ViewModel.CustomerViewModel

<h2> Edit </h2>
<div align="center" width="500px">
    @using (Html.BeginForm("Edit", "Customer", FormMethod.Post))
    {
        <table class="table"
               width="400px"
               cellpadding="20">
            <tr class="btn-default">
                <td>
                    @Html.LabelFor(model => model.customer.Name)
                </td>

                <td>
                    @Html.TextBoxFor(model => model.customer.Name)
                </td>
            </tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.customer.Address)
                </td>

                <td>
                    @Html.TextBoxFor(model => model.customer.Address)
                </td>
            </tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.customer.MobileNo)
                </td>

                <td>
                    @Html.TextBoxFor(model => model.customer.MobileNo)
                </td>
            </tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.customer.Birthdate)
                </td>

                <td>
                    @Html.TextBoxFor(model => model.customer.Birthdate)
                </td>
            </tr>
            <tr>
                <td>
                    @Html.LabelFor(model => model.customer.EmailId)
                </td>

                <td>
                    @Html.TextBoxFor(model => model.customer.EmailId)
                </td>
            </tr>
            <tr>
                <td> </td>

                <td>
                    <input type="submit" value="保存" /> &nbsp; <a class="btn-primary" href="@Url.Action("Index ","Customer ")"> 返回 </a>
                    @Html.HiddenFor(model => model.customer.CustomerId)
                </td>
            </tr>
        </table>
    }
</div>

最终项目代码已经完成了。这时候我们运行项目试试看了。但还有一点要注意的是，我们必须同时运行web api和mvc项目。怎么办呢？其实只要在项目属性里设置就可以了。

• 右键解决方案，选择属性(Properties)。

• 接来下在启动项目选项中，选择多项目启动,在Action中设置两个项目同时启动。

• 运行项目，看看CRUD操作的执行结果。

Select

Insert

Update

Delete

这是整个技术预研的过程，本文末尾位置提供代码下载。

 作者：阿子
 博客地址：http://www.cnblogs.com/yayazi/