在MVC程序中，使用泛型仓储模式和工作单元实现增删查改

在这片文章中，我将自己动手为所有的实体：写一个泛型仓储类，还有一个工作单元。

工作单元的职责就是：为每一个实体，创建仓储实例。仓储（仓库）的职责：增删查改的功能实现。

我们将会在控制器中，创建工作单元类（UnitOfWork）的实例，然后根据实体，创建仓储实例，再就是使用仓储里面的方法，做操作了。

下面的图中，解释了，仓储和EF 数据上文的关系，在这个图里面，MVC控制器和仓储之间的交互，是通过工作单元来进行的，而不是直接和EF接触。

那么你可能就要问了，为什么要使用工作单元？？？

工作单元，就像其名称一样，做某些事情。在这篇文章中，工作单元主要是，创建实例：它实例化数据上下文，然后使用同样的数据上下文对象，实例化每一个仓储对象，用来做数据库操作。所以： 工作单元是一种模式，它确保我们所有的仓储类，使用同样数据库上下文。

实现一个泛型仓储类和一个工作单元

请注意：在这篇文章中，你的用户界面，使用具体的类，而不是接口，原因，我后面的一篇文章中，会说！

好了，现在开始实施：

在这篇文章中，我将会搭建4个项目。

MVC.Core---->>>类库项目【这里面：主要是实体的声明】

MVC.Data---->>>类库项目【这里面主要是数据库的操作，添加引用类库项目（MVC.Core）】

MVC.Repository--->>>类库项目【这里主要是定义泛型仓储类，添加引用MVC.Core和MVC.Data两个项目】

MVC.Web----->>>MVC WEB程序【Web程序UI，添加引用MVC.Core和MVC.Data还有MVC.Repository三个项目】

框架的界面：

首先来写实体层：在MVC.Core项目下，添加一个BaseEntity实体，添加如下代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace MVC.Core{    public class BaseEntity    {        /// <summary>        /// 编号        /// </summary>        public Int64 ID { get; set; }        /// <summary>        /// 添加时间        /// </summary>        public DateTime AddedTime { get; set; }        /// <summary>        /// 修改时间        /// </summary>        public DateTime ModifiedTime { get; set; }        /// <summary>        /// IP地址        /// </summary>        public string IP { get; set; }    }}

然后，在MVC.Core项目下，新建一个文件夹【Data】,在【Data】文件夹里面添加Book实体，Book继承BaseEntity实体。

下面是Book实体里面的代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace MVC.Core.Data{   public class Book:BaseEntity    {       /// <summary>       /// 书名       /// </summary>       public string Title { get; set; }       /// <summary>       /// 作者       /// </summary>       public string Author { get; set; }       /// <summary>       /// ISBN编号       /// </summary>       public string ISBN { get; set; }       /// <summary>       /// 发布时间       /// </summary>       public DateTime PublishedTime { get; set; }    }}

然后，我们看到MVC.Data这个类库项目，这个项目中，我们将会包含数据上下文类，Book实体的映射。

ADO.NET Entity Framework 要求我们创建的数据上下文类必须继承DbContext类。我们在上下文类中，将会重写OnModelCreating方法，这个方法是用来使用Code-First方式，配置实体类的。

使用EF，需要安装EF，这里就不介绍了，要了解的话，可以去看我前面的文章中的介绍。

我创建一个EFDbContextClass类，下面是数据上下文类中的代码：

using MVC.Core;using System;using System.Collections.Generic;using System.Data.Entity;using System.Data.Entity.ModelConfiguration;using System.Linq;using System.Reflection;using System.Text;using System.Threading.Tasks;namespace MVC.Data{    public class EFDBContextClass:DbContext    {        public EFDBContextClass() : base("name=ConnectionStrings")         {         }        public new IDbSet<TEntity> Set<TEntity>() where TEntity:BaseEntity        {            return base.Set<TEntity>();        }        protected override void OnModelCreating(DbModelBuilder modelBuilder)        {                        var typesToRegister = Assembly.GetExecutingAssembly().GetTypes()           .Where(type => !String.IsNullOrEmpty(type.Namespace))           .Where(type => type.BaseType != null && type.BaseType.IsGenericType                && type.BaseType.GetGenericTypeDefinition() == typeof(EntityTypeConfiguration<>));            foreach (var type in typesToRegister)            {                dynamic configurationInstance = Activator.CreateInstance(type);                modelBuilder.Configurations.Add(configurationInstance);            }            base.OnModelCreating(modelBuilder);        }            }}

在上面的代码中，使用反射来映射每个实体。然后数据上下文的构造函数中，我传递了连接字符串名字ConnectionStrings,在配置文件中

<connectionStrings>    <add name="ConnectionStrings" connectionString="server=.;database=MyRepositoryDB;uid=sa;pwd=Password_1" providerName="System.Data.SqlClient"/>  </connectionStrings>

好了，数据上下文也写好了，现在开始实体映射吧，在MVC.Data项目中，添加一个文件夹--【Mapping】，然后在Mapping文件夹下面，添加一个类--【BookMap】，下面是BookMap的代码：

using MVC.Core.Data;using System;using System.Collections.Generic;using System.Data.Entity.ModelConfiguration;using System.Linq;using System.Text;using System.Threading.Tasks;using System.ComponentModel.DataAnnotations.Schema;namespace MVC.Data.Mapping{   public class BookMap:EntityTypeConfiguration<Book>    {       public BookMap()       {           //配置主键           HasKey(s => s.ID);           //配置列           Property(s => s.ID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);           Property(p => p.Title).IsRequired();           Property(p => p.ISBN).IsRequired();           Property(p => p.Author).IsRequired();           Property(p => p.AddedTime).IsRequired();           Property(p => p.ModifiedTime).IsRequired();           Property(p => p.PublishedTime).IsRequired();           Property(p => p.IP);           //配置表名称           ToTable("Books");                  }    }}

好了，现在开始写我们的泛型仓储类，在我们的MVC.Repository项目中，添加一个类Repository。这里没有添加接口仓储，是为了更好的理解。泛型仓储类拥有增删查改的方法，

这个仓储类，拥有一个带数据上下文类的参数的构造函数，所以当我们创建创建仓储实例的时候，只需要传递一个数据上下文对象过来就行，这就一样，每个实体的仓储都有一样的数据上下文对象了。下面的代码是，泛型仓储模式代码了：

using MVC.Core;using MVC.Data;using System;using System.Collections.Generic;using System.Data.Entity;using System.Data.Entity.Validation;using System.Linq;using System.Text;using System.Threading.Tasks;namespace MVC.Repository{    public class Repository<T> where T:BaseEntity    {        private EFDBContextClass context;        private IDbSet<T> entities;              string errorMessage = string.Empty;        public Repository(EFDBContextClass context)        {            this.context = context;        }               public T GetById(object id)        {            return this.Entities.Find(id);        }        public void Insert(T entity)        {            try            {                if (entity == null)                {                    throw new ArgumentNullException("entity");                }                this.Entities.Add(entity);                this.context.SaveChanges();            }            catch (DbEntityValidationException ex)            {                //错误处理机制                foreach (var validationErros in ex.EntityValidationErrors)                {                    foreach (var errorInfo in validationErros.ValidationErrors)                    {                        errorMessage += string.Format("属性:{0} 错误消息:{1}", errorInfo.PropertyName, errorInfo.ErrorMessage) + Environment.NewLine;                    }                }                throw new Exception(errorMessage, ex);            }        }        public void Update(T entity)        {            try            {                if (entity == null)                {                    throw new ArgumentNullException("entity");                }                this.context.SaveChanges();            }            catch (DbEntityValidationException ex)            {                foreach (var errorItems in ex.EntityValidationErrors)                {                    foreach (var errorinfo in errorItems.ValidationErrors)                    {                        errorMessage += string.Format("属性名:{0},错误消息:{1}", errorinfo.PropertyName, errorinfo.ErrorMessage) + Environment.NewLine;                    }                }                throw new Exception(errorMessage, ex);            }        }        public void Delete(T entity)        {             try            {                         if (entity == null)                {                    throw new ArgumentNullException("entity");                }                this.Entities.Remove(entity);                this.context.SaveChanges();            }            catch (DbEntityValidationException ex)            {                foreach (var errorItems in ex.EntityValidationErrors)                {                    foreach (var errorinfo in errorItems.ValidationErrors)                    {                        errorMessage += string.Format("属性名:{0},错误消息:{1}", errorinfo.PropertyName, errorinfo.ErrorMessage) + Environment.NewLine;                    }                }                throw new Exception(errorMessage, ex);            }        }        private IDbSet<T> Entities        {            get            {                if (entities == null)                {                    entities = context.Set<T>();                }                return entities;            }        }        public virtual IQueryable<T> Table        {            get             {                return this.Entities;            }        }    }}

在MVC.Repository项目中添加一个类：UnitOfWork

现在来为工作单元创建一个类，UnitOfWork，这个类继承IDisposible接口，所以它的每个实例将会在控制器中销毁，这个工作单元，初始化程序的数据上下文类【EFDBContextClass】.这个工作单元类的核心就是Repository方法，这个方法，为每一个继承自BaseEntity的实体，返回一个仓储【repository】对象，下面是工作单元类的代码：

using MVC.Core;using MVC.Data;using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace MVC.Repository{   public class UnitOfWork:IDisposable    {       private readonly EFDBContextClass context;       private bool disposed;       private Dictionary<string, object> repositories;       public UnitOfWork(EFDBContextClass context)       {           this.context = context;       }       public UnitOfWork()       {           context = new EFDBContextClass();       }       public void Dispose()       {           Dispose(true);           GC.SuppressFinalize(this);       }       public void Save()       {           context.SaveChanges();       }       public virtual void Dispose(bool disposing)       {           if (!disposed)           {               if (disposing)               {                   context.Dispose();               }           }           disposed = true;       }       public Repository<T> Repository<T>() where T : BaseEntity       {           if (repositories == null)           {               repositories = new Dictionary<string, object>();           }           var type = typeof(T).Name;           if (!repositories.ContainsKey(type))           {               var repositoryType = typeof(Repository<>);               var repositoryInstance = Activator.CreateInstance(repositoryType.MakeGenericType(typeof(T)), context);               repositories.Add(type, repositoryInstance);           }           return (Repository<T>)repositories[type];       }    }}

到此，现在底层的代码,基本都写好了。

现在开始MVC.Web项目里面的代码：

首先，我们在控制器文件夹下面，新建一个控制器类，BookController。然后，我们创建工作单元的实例。

下面是BookController控制器的代码：

using MVC.Core.Data;using MVC.Data;using MVC.Repository;using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.Mvc;namespace MVC.Web.Controllers{    public class BookController : Controller    {        private UnitOfWork unitOfWork = new UnitOfWork();        private Repository<Book> bookRepository;        public BookController()        {            //通过工作单元来初始化仓储            bookRepository = unitOfWork.Repository<Book>();        }        // GET: Book        public ActionResult Index()        {          List<Book> listBooks=  bookRepository.Table.ToList();          return View(listBooks);        }        public ActionResult CreateEditBook(int? id)        {            Book bookModel = new Book();            if (id.HasValue)            {                bookModel = bookRepository.GetById(id.Value);            }            return View(bookModel);        }        [HttpPost]        public ActionResult CreateEditBook(Book model)        {            if (model.ID == 0)            {                model.ModifiedTime = DateTime.Now;                model.AddedTime = DateTime.Now;                model.IP = Request.UserHostAddress;                bookRepository.Insert(model);            }            else            {                var editModel = bookRepository.GetById(model.ID);                editModel.Title = model.Title;                editModel.Author = model.Author;                editModel.ISBN = model.ISBN;                editModel.PublishedTime = model.PublishedTime;                editModel.ModifiedTime = System.DateTime.Now;                editModel.IP = Request.UserHostAddress;                bookRepository.Update(editModel);                        }            if (model.ID > 0)            {                return RedirectToAction("Index");            }            return View(model);        }        public ActionResult DeleteBook(int id)        {          Book model=  bookRepository.GetById(id);          return View(model);                 }        [HttpPost,ActionName("DeleteBook")]        public ActionResult ConfirmDeleteBook(int id)        {          Book model=  bookRepository.GetById(id);          bookRepository.Delete(model);          return RedirectToAction("Index");        }        public ActionResult DetailBook(int id)        {          Book model=  bookRepository.GetById(id);          return View(model);        }        protected override void Dispose(bool disposing)        {            unitOfWork.Dispose();            base.Dispose(disposing);        }    }}

现在已经完成了控制器的方法，开始添加视图了：

CreateEdit：

@model MVC.Core.Data.Book@{    ViewBag.Title = "Create Edit Book";}<div class="book-example panel panel-primary">    <div class="panel-heading panel-head">Add / Edit Book</div>    <div class="panel-body">        @using (Html.BeginForm())        {            <div class="form-horizontal">                <div class="form-group">                    @Html.LabelFor(model => model.Title,                    new { @class = "col-lg-1 control-label" })                    <div class="col-lg-9">                        @Html.TextBoxFor(model => model.Title,                        new { @class = "form-control" })                    </div>                </div>                <div class="form-group">                    @Html.LabelFor(model => model.ISBN,                    new { @class = "col-lg-1 control-label" })                    <div class="col-lg-9">                        @Html.TextBoxFor(model => model.ISBN,                        new { @class = "form-control" })                    </div>                </div>                <div class="form-group">                    @Html.LabelFor(model => model.Author,                    new { @class = "col-lg-1 control-label" })                    <div class="col-lg-9">                        @Html.TextBoxFor(model => model.Author,                        new { @class = "form-control" })                    </div>                </div>                <div class="form-group">                    @Html.LabelFor(model => model.PublishedTime,                    new { @class = "col-lg-1 control-label" })                    <div class="col-lg-9">                        @Html.TextBoxFor(model => model.PublishedTime,                        new { @class = "form-control datepicker" })                    </div>                </div>                <div class="form-group">                    <div class="col-lg-8"></div>                    <div class="col-lg-3">                        @Html.ActionLink("Back to List", "Index",                        null, new { @class = "btn btn-default" })                        <button class="btn btn-success"                                id="btnSubmit" type="submit">                            Submit                        </button>                    </div>                </div>            </div>        }    </div></div>@section scripts{    <script src="~/Scripts/bootstrap-datepicker.js" type="text/javascript"></script>    <script src="~/Scripts/book-create-edit.js" type="text/javascript"></script>} 

DeleteBook：

@model MVC.Core.Data.Book@{    ViewBag.Title = "Delete Book";}<div class="book-example panel panel-primary">    <div class="panel-heading panel-head">Delete Book</div>    <div class="panel-body">        <h3>Are you sure you want to delete this?</h3>        <h1>@ViewBag.ErrorMessage</h1>        <div class="form-horizontal">            <div class="form-group">                @Html.LabelFor(model => model.Title,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.Title,                    new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.Author,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.Author,                    new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.ISBN,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.ISBN,                    new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.PublishedTime,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.PublishedTime,                    new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.AddedTime,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.AddedTime,                    new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.ModifiedTime,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.ModifiedTime,                    new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.IP,                new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.IP,                    new { @class = "form-control" })                </div>            </div>            @using (Html.BeginForm())            {                <div class="form-group">                    <div class="col-lg-1"></div>                    <div class="col-lg-9">                        <input type="submit" value="Delete"                               class="btn btn-danger" />                        @Html.ActionLink("Back to List", "Index",                        null, new { @class = "btn btn-success" })                    </div>                </div>            }        </div>    </div></div>  

DetailBook：

@model MVC.Core.Data.Book@{    ViewBag.Title = "Detail Book";}<div class="book-example panel panel-primary">    <div class="panel-heading panel-head">Book Detail</div>    <div class="panel-body">        <div class="form-horizontal">            <div class="form-group">                @Html.LabelFor(model => model.Title, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.Title, new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.Author, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.Author, new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.ISBN, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.ISBN, new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.PublishedTime, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.PublishedTime, new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.AddedTime, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.AddedTime, new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.ModifiedTime, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.ModifiedTime, new { @class = "form-control" })                </div>            </div>            <div class="form-group">                @Html.LabelFor(model => model.IP, new { @class = "col-lg-1 control-label" })                <div class="col-lg-9">                    @Html.DisplayFor(model => model.IP, new { @class = "form-control" })                </div>            </div>            @using (Html.BeginForm())            {                <div class="form-group">                    <div class="col-lg-1"></div>                    <div class="col-lg-9">                        @Html.ActionLink("Edit", "CreateEditBook",                        new { id = Model.ID }, new { @class = "btn btn-primary" })                        @Html.ActionLink("Back to List", "Index",                        null, new { @class = "btn btn-success" })                    </div>                </div>            }        </div>    </div></div>   

Index：

@model IEnumerable<MVC.Core.Data.Book><div class="book-example panel panel-primary">    <div class="panel-heading panel-head">Books Listing</div>    <div class="panel-body">        <a id="createEditBookModal"           href="@Url.Action("CreateEditBook")" class="btn btn-success">            <span class="glyphicon glyphicon-plus"></span>Book        </a>        <table class="table" style="margin: 4px">            <tr>                <th>                    @Html.DisplayNameFor(model => model.Title)                </th>                <th>                    @Html.DisplayNameFor(model => model.Author)                </th>                <th>                    @Html.DisplayNameFor(model => model.ISBN)                </th>                <th>                    Action                </th>                <th></th>            </tr>            @foreach (var item in Model)            {                <tr>                    <td>                        @Html.DisplayFor(modelItem => item.Title)                    </td>                    <td>                        @Html.DisplayFor(modelItem => item.Author)                    </td>                    <td>                        @Html.DisplayFor(modelItem => item.ISBN)                    </td>                    <td>                        @Html.ActionLink("Edit", "CreateEditBook",                        new { id = item.ID }, new { @class = "btn btn-success" }) |                        @Html.ActionLink("Details", "DetailBook",                        new { id = item.ID }, new { @class = "btn btn-primary" }) |                        @Html.ActionLink("Delete", "DeleteBook",                        new { id = item.ID }, new { @class = "btn btn-danger" })                    </td>                </tr>            }        </table>    </div></div> 

效果图：