MVC项目结构搭建及单个类的实现学习笔记1

2016-12-08 15:50:37  MVC项目

新人刚开始学习ASP MVC,若有不足之处希望能得到您的指点,不胜感激!

先来一张项目的层级结构图:

MVC项目结构搭建及单个类的实现学习笔记1

Model:模型层,主要是各种类型、枚举以及ORM框架,框架完成数据库和实体类的映射。项目中选用了微软的开源ORM框架 EntityFramework 6.0 (以下简称EF),数据库则选择了微软的轻量级数据库SQL Server Compact 4.0本地数据库(简称Compact),Compact对EF支持比较完美,又属于文档型数据库,部署起来比较简洁。

DAL:数据访问层,主要是对数据库的操作层,为业务逻辑层或表示层提供数据服务。

IDAL:数据访问接口层,是数据访问层的接口,降低耦合。

DALFactory:数据会话层,封装了所有数据操作类实例的创建,将数据访问层与业务逻辑层解耦。

BLL:业务逻辑层,主要负责对数据层的操作,把一些数据层的操作进行组合以完成业务的需要。

IBLL:业务逻辑接口层,业务逻辑层的接口,降低耦合。

WebApp:表现层,是一个ASP MVC项目,完成具体网站的实现。

Common:通用层,用来存放一些工具类。

下面是各个层级之间具体的实现,首先创建以 项目名.层级名 命名的各个层次,除WebApp层为ASP MVC项目外,其余均创建为类库项目。

MVC项目结构搭建及单个类的实现学习笔记1

模型层的构建

先建立模型层,新建ASP 实体数据模型,关联到已经设计好的数据库,EF自动完成模型类的创建。

MVC项目结构搭建及单个类的实现学习笔记1

数据访问层的构建

      DAL层中,我们首先需要一个方法来获取单例的EF数据操纵上下文对象,以保证每个用户访问时只有使用一个上下文对象对数据库进行操作。

DbContextFactory.cs

using System.Data.Entity; using System.Runtime.Remoting.Messaging; using PMS.Model; namespace PMS.DAL { public class DbContextFactory { /// <summary> /// 负责创建EF数据操作上下文实例,必须保证线程内唯一 /// </summary> public static DbContext CreateContext() { DbContext dbContext = (DbContext)CallContext.GetData("dbContext"); if (dbContext != null) return dbContext; dbContext = new PMSEntities(); CallContext.SetData("dbContext", dbContext); return dbContext; } } }  

为User类创建DAL层,实现查询、分页查询、增加、删除和修改这五个基本的方法:

UserDAL.cs

using System; using System.Data.Entity; using System.Linq; using PMS.IDAL; namespace PMS.DAL { public partial class UserDal { public DbContext DbEntities = DbContextFactory.CreateContext(); /// <summary> /// 查询过滤 /// </summary> /// <param name="whereLamada">过滤条件Lambda表达式</param> /// <returns>实体集合</returns> public IQueryable<UserDal> LoadEntities(System.Linq.Expressions.Expression<Func<UserDal, bool>> whereLamada) { return DbEntities.Set<UserDal>().Where(whereLamada); } /// <summary> /// 分页查询 /// </summary> /// <typeparam name="TS">排序类型</typeparam> /// <param name="pageIndex">查询的页码</param> /// <param name="pageSize">每页显示的数目</param> /// <param name="totalCount">符合条件的总行数</param> /// <param name="whereLambda">过滤条件Lambda表达式</param> /// <param name="orderbyLambda">排序Lambda表达式</param> /// <param name="isAsc">排序方向</param> /// <returns>实体集合</returns> public IQueryable<UserDal> LoadPageEntities<TS>(int pageIndex, int pageSize, out int totalCount, System.Linq.Expressions.Expression<Func<UserDal, bool>> whereLambda, System.Linq.Expressions.Expression<Func<UserDal, TS>> orderbyLambda, bool isAsc) { var temp = DbEntities.Set<UserDal>().Where(whereLambda); totalCount = temp.Count(); temp = isAsc ? temp.OrderBy(orderbyLambda).Skip((pageIndex - 1) * pageSize).Take(pageSize) : temp.OrderByDescending(orderbyLambda).Skip((pageIndex - 1) * pageSize).Take(pageSize); return temp; } /// <summary> /// 删除数据 /// </summary> /// <param name="entity">待删数据</param> /// <returns>删除结果</returns> public bool DeleteEntity(UserDal entity) { DbEntities.Entry(entity).State = EntityState.Deleted; return true; } /// <summary> /// 编辑数据 /// </summary> /// <param name="entity">待编辑数据</param> /// <returns>编辑结果</returns> public bool EditEntity(UserDal entity) { DbEntities.Entry(entity).State = EntityState.Modified; return true; } /// <summary> /// 添加数据 /// </summary> /// <param name="entity">待添加数据</param> /// <returns>已添加数据</returns> public UserDal AddEntity(UserDal entity) { entity = DbEntities.Set<UserDal>().Add(entity); return entity; } } }

注:这里的增删改操作并不即时进行,而是在封装在数据会话层中,以实现工作单元模式,提高数据库的操作效率。

考虑到每个类都需要实现相同的数据操作,我们可以将以上方法封装到一个泛型基类中,各类型只需要继承泛型基类就可以实现以上方法:

BaseDal.cs

using System; using System.Data.Entity; using System.Linq; namespace PMS.DAL { public class BaseDal<T> where T:class ,new() { public DbContext DbEntities = DbContextFactory.CreateContext(); /// <summary> /// 查询过滤 /// </summary> /// <param name="whereLamada">过滤条件Lambda表达式</param> /// <returns>实体集合</returns> public IQueryable<T> LoadEntities(System.Linq.Expressions.Expression<Func<T, bool>> whereLamada) { return DbEntities.Set<T>().Where(whereLamada); } /// <summary> /// 分页查询 /// </summary> /// <typeparam name="TS">排序类型</typeparam> /// <param name="pageIndex">查询的页码</param> /// <param name="pageSize">每页显示的数目</param> /// <param name="totalCount">符合条件的总行数</param> /// <param name="whereLambda">过滤条件Lambda表达式</param> /// <param name="orderbyLambda">排序Lambda表达式</param> /// <param name="isAsc">排序方向</param> /// <returns>实体集合</returns> public IQueryable<T> LoadPageEntities<TS>(int pageIndex, int pageSize, out int totalCount, System.Linq.Expressions.Expression<Func<T, bool>> whereLambda, System.Linq.Expressions.Expression<Func<T, TS>> orderbyLambda, bool isAsc) { var temp = DbEntities.Set<T>().Where(whereLambda); totalCount = temp.Count(); temp = isAsc ? temp.OrderBy(orderbyLambda).Skip((pageIndex - 1) * pageSize).Take(pageSize) : temp.OrderByDescending(orderbyLambda).Skip((pageIndex - 1) * pageSize).Take(pageSize); return temp; } /// <summary> /// 删除数据 /// </summary> /// <param name="entity">待删数据</param> /// <returns>删除结果</returns> public bool DeleteEntity(T entity) { DbEntities.Entry(entity).State = EntityState.Deleted; return true; } /// <summary> /// 编辑数据 /// </summary> /// <param name="entity">待编辑数据</param> /// <returns>编辑结果</returns> public bool EditEntity(T entity) { DbEntities.Entry(entity).State = EntityState.Modified; return true; } /// <summary> /// 添加数据 /// </summary> /// <param name="entity">待添加数据</param> /// <returns>已添加数据</returns> public T AddEntity(T entity) { entity = DbEntities.Set<T>().Add(entity); //DbEntities.SaveChanges(); return entity; } } }

UserDal继承BaseDal

using PMS.IDAL; using PMS.Model; namespace PMS.DAL { public partial class UserDal : BaseDal<User> { } }

数据访问接口层的构建

然后我们建立相应的IbaseDal接口和IUserDal接口,并且使UserDal类实现IUserDal接口

IBaseDal:

using System; using System.Linq; namespace PMS.IDAL { public interface IBaseDal<T> where T:class,new() { IQueryable<T> LoadEntities(System.Linq.Expressions.Expression<Func<T, bool>> whereLamada); IQueryable<T> LoadPageEntities<s>(int pageIndex, int pageSize, out int totalCount, System.Linq.Expressions.Expression<Func<T, bool>> whereLambda, System.Linq.Expressions.Expression<Func<T, s>> orderbyLambda, bool isAsc); bool DeleteEntity(T entity); bool EditEntity(T entity); T AddEntity(T entity); } }

IUserDal:

using PMS.Model; namespace PMS.IDAL { public partial interface IUserDal:IBaseDal<User> { } }

UserDal实现IUserDal接口:

public partial class UserDal : BaseDal<User>,IUserDal

数据会话层的构建

抽象工厂类AbstractFactory:

using System.Configuration; using System.Reflection; using PMS.IDAL; namespace PMS.DALFactory { public partial class AbstractFactory { //读取保存在配置文件中的程序集名称与命名空间名 private static readonly string AssemblyPath = ConfigurationManager.AppSettings["AssemblyPath"]; private static readonly string NameSpace = ConfigurationManager.AppSettings["NameSpace"]; /// <summary> /// 获取UserDal的实例 /// </summary> /// <returns></returns> public static IUserDal CreateUserInfoDal() { var fullClassName = NameSpace + ".UserInfoDal"; return CreateInstance(fullClassName) as IUserDal; } /// <summary> /// 通过反射获得程序集中某类型的实例 /// </summary> /// <param name="className"></param> /// <returns></returns> private static object CreateInstance(string className) { var assembly = Assembly.Load(AssemblyPath); return assembly.CreateInstance(className); } } }

数据会话类DbSession:

using System.Data.Entity; using PMS.IDAL; using PMS.DAL; namespace PMS.DALFactory { public partial class DbSession:IDbSession { public DbContext Db { get { return DbContextFactory.CreateContext(); } } private IUserDal _userDal; public IUserDal UserDal { get { return _userDal ?? (_userDal = AbstractFactory.CreateUserInfoDal()); } set { _userDal = value; } } /// <summary> /// 工作单元模式,统一保存数据 /// </summary> /// <returns></returns> public bool SaveChanges() { return Db.SaveChanges() > 0; } } }

业务逻辑层的构建

业务类基类BaseService

using System; using System.Linq; using System.Linq.Expressions; using PMS.DALFactory; using PMS.IDAL; namespace PMS.BLL { public abstract class BaseService<T> where T:class,new() { public IDbSession CurrentDbSession { get { return new DbSession(); } } public IBaseDal<T> CurrentDal { get; set; } public abstract void SetCurrentDal(); public BaseService() { SetCurrentDal();//子类一定要实现抽象方法,以指明当前类的子类类型。 } /// <summary> /// 查询过滤 /// </summary> /// <param name="whereLambda"></param> /// <returns></returns> public IQueryable<T> LoadEntities(Expression<Func<T, bool>> whereLambda) { return CurrentDal.LoadEntities(whereLambda); } /// <summary> /// 分页 /// </summary> /// <typeparam name="s"></typeparam> /// <param name="pageIndex"></param> /// <param name="pageSize"></param> /// <param name="totalCount"></param> /// <param name="whereLambda"></param> /// <param name="orderbyLambda"></param> /// <param name="isAsc"></param> /// <returns></returns> public IQueryable<T> LoadPageEntities<s>(int pageIndex, int pageSize, out int totalCount, Expression<Func<T, bool>> whereLambda, Expression<Func<T, s>> orderbyLambda, bool isAsc) { return CurrentDal.LoadPageEntities<s>(pageIndex, pageSize, out totalCount, whereLambda, orderbyLambda, isAsc); } /// <summary> /// 删除 /// </summary> /// <param name="entity"></param> /// <returns></returns> public bool DeleteEntity(T entity) { CurrentDal.DeleteEntity(entity); return CurrentDbSession.SaveChanges(); } /// <summary> /// 编辑 /// </summary> /// <param name="entity"></param> /// <returns></returns> public bool EditEntity(T entity) { CurrentDal.EditEntity(entity); return CurrentDbSession.SaveChanges(); } /// <summary> /// 添加数据 /// </summary> /// <param name="entity"></param> /// <returns></returns> public T AddEntity(T entity) { CurrentDal.AddEntity(entity); CurrentDbSession.SaveChanges(); return entity; } } }

UserService类:

using PMS.IBLL; using PMS.Model; namespace PMS.BLL { public partial class UserService : BaseService<User> { public override void SetCurrentDal() { CurrentDal = CurrentDbSession.UserDal; } } }  

业务逻辑接口层的构建

直接建立对应的接口并使用UserService类实现IUserService接口

IBaseService接口:

using System; using System.Linq; using System.Linq.Expressions; using PMS.IDAL; namespace PMS.IBLL { public interface IBaseService<T> where T : class,new() { IDbSession CurrentDbSession { get; } IBaseDal<T> CurrentDal { get; set; } void SetCurrentDal(); IQueryable<T> LoadEntities(Expression<Func<T, bool>> whereLambda); IQueryable<T> LoadPageEntities<s>(int pageIndex, int pageSize, out int totalCount, Expression<Func<T, bool>> whereLambda, Expression<Func<T, s>> orderbyLambda, bool isAsc); bool DeleteEntity(T entity); bool EditEntity(T entity); T AddEntity(T entity); } }

IUserService接口:

using PMS.Model; namespace PMS.IBLL { public partial interface IUserService:IBaseService<User> { } }

使用UserService类实现IUserService接口:

public partial class UserService : BaseService<User>, IUserService  

以上我们就完成了整个框架中关于User类的各层次的实现。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。

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