????? 新人剛開始學(xué)習(xí)ASP.NET MVC，若有不足之處希望能得到您的指點，不勝感激！

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?????? 先來一張項目的層級結(jié)構(gòu)圖:

????? Model：模型層，主要是各種類型、枚舉以及ORM框架，框架完成數(shù)據(jù)庫和實體類的映射。項目中選用了微軟的開源ORM框架 EntityFramework 6.0 （以下簡稱EF），數(shù)據(jù)庫則選擇了微軟的輕量級數(shù)據(jù)庫SQL Server Compact 4.0本地數(shù)據(jù)庫（簡稱Compact），Compact對EF支持比較完美，又屬于文檔型數(shù)據(jù)庫，部署起來比較簡潔。

????? DAL：數(shù)據(jù)訪問層，主要是對數(shù)據(jù)庫的操作層，為業(yè)務(wù)邏輯層或表示層提供數(shù)據(jù)服務(wù)。

????? IDAL：數(shù)據(jù)訪問接口層，是數(shù)據(jù)訪問層的接口，降低耦合。

????? DALFactory：數(shù)據(jù)會話層，封裝了所有數(shù)據(jù)操作類實例的創(chuàng)建，將數(shù)據(jù)訪問層與業(yè)務(wù)邏輯層解耦。

????? BLL：業(yè)務(wù)邏輯層，主要負(fù)責(zé)對數(shù)據(jù)層的操作，把一些數(shù)據(jù)層的操作進行組合以完成業(yè)務(wù)的需要。

????? IBLL：業(yè)務(wù)邏輯接口層，業(yè)務(wù)邏輯層的接口，降低耦合。

????? WebApp：表現(xiàn)層，是一個ASP.NET MVC項目，完成具體網(wǎng)站的實現(xiàn)。

????? Common：通用層，用來存放一些工具類。

????? 下面是各個層級之間具體的實現(xiàn)，首先創(chuàng)建以 項目名.層級名 命名的各個層次，除WebApp層為ASP.NET MVC項目外，其余均創(chuàng)建為類庫項目。

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模型層的構(gòu)建

????? 先建立模型層，新建ASP.NET 實體數(shù)據(jù)模型，關(guān)聯(lián)到已經(jīng)設(shè)計好的數(shù)據(jù)庫，EF自動完成模型類的創(chuàng)建。

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數(shù)據(jù)訪問層的構(gòu)建

????? DAL層中，我們首先需要一個方法來獲取單例的EF數(shù)據(jù)操縱上下文對象，以保證每個用戶訪問時只有使用一個上下文對象對數(shù)據(jù)庫進行操作。DbContextFactory.cs

using System.Data.Entity; using System.Runtime.Remoting.Messaging; using PMS.Model;namespace PMS.DAL {public class DbContextFactory{/// <summary>/// 負(fù)責(zé)創(chuàng)建EF數(shù)據(jù)操作上下文實例,必須保證線程內(nèi)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;}} }

????? 為User類創(chuàng)建DAL層，實現(xiàn)查詢、分頁查詢、增加、刪除和修改這五個基本的方法：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>/// 查詢過濾/// </summary>/// <param name="whereLamada">過濾條件Lambda表達(dá)式</param>/// <returns>實體集合</returns>public IQueryable<UserDal> LoadEntities(System.Linq.Expressions.Expression<Func<UserDal, bool>> whereLamada){return DbEntities.Set<UserDal>().Where(whereLamada);}/// <summary>/// 分頁查詢/// </summary>/// <typeparam name="TS">排序類型</typeparam>/// <param name="pageIndex">查詢的頁碼</param>/// <param name="pageSize">每頁顯示的數(shù)目</param>/// <param name="totalCount">符合條件的總行數(shù)</param>/// <param name="whereLambda">過濾條件Lambda表達(dá)式</param>/// <param name="orderbyLambda">排序Lambda表達(dá)式</param>/// <param name="isAsc">排序方向</param>/// <returns>實體集合</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>/// 刪除數(shù)據(jù)/// </summary>/// <param name="entity">待刪數(shù)據(jù)</param>/// <returns>刪除結(jié)果</returns>public bool DeleteEntity(UserDal entity){DbEntities.Entry(entity).State = EntityState.Deleted;return true;}/// <summary>/// 編輯數(shù)據(jù)/// </summary>/// <param name="entity">待編輯數(shù)據(jù)</param>/// <returns>編輯結(jié)果</returns>public bool EditEntity(UserDal entity){DbEntities.Entry(entity).State = EntityState.Modified;return true;}/// <summary>/// 添加數(shù)據(jù)/// </summary>/// <param name="entity">待添加數(shù)據(jù)</param>/// <returns>已添加數(shù)據(jù)</returns>public UserDal AddEntity(UserDal entity){entity = DbEntities.Set<UserDal>().Add(entity);return entity;} } }

注：這里的增刪改操作并不即時進行，而是在封裝在數(shù)據(jù)會話層中，以實現(xiàn)工作單元模式，提高數(shù)據(jù)庫的操作效率。

????? 考慮到每個類都需要實現(xiàn)相同的數(shù)據(jù)操作，我們可以將以上方法封裝到一個泛型基類中，各類型只需要繼承泛型基類就可以實現(xiàn)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>/// 查詢過濾/// </summary>/// <param name="whereLamada">過濾條件Lambda表達(dá)式</param>/// <returns>實體集合</returns>public IQueryable<T> LoadEntities(System.Linq.Expressions.Expression<Func<T, bool>> whereLamada){return DbEntities.Set<T>().Where(whereLamada);}/// <summary>/// 分頁查詢/// </summary>/// <typeparam name="TS">排序類型</typeparam>/// <param name="pageIndex">查詢的頁碼</param>/// <param name="pageSize">每頁顯示的數(shù)目</param>/// <param name="totalCount">符合條件的總行數(shù)</param>/// <param name="whereLambda">過濾條件Lambda表達(dá)式</param>/// <param name="orderbyLambda">排序Lambda表達(dá)式</param>/// <param name="isAsc">排序方向</param>/// <returns>實體集合</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>/// 刪除數(shù)據(jù)/// </summary>/// <param name="entity">待刪數(shù)據(jù)</param>/// <returns>刪除結(jié)果</returns>public bool DeleteEntity(T entity){DbEntities.Entry(entity).State = EntityState.Deleted;return true;}/// <summary>/// 編輯數(shù)據(jù)/// </summary>/// <param name="entity">待編輯數(shù)據(jù)</param>/// <returns>編輯結(jié)果</returns>public bool EditEntity(T entity){DbEntities.Entry(entity).State = EntityState.Modified;return true;}/// <summary>/// 添加數(shù)據(jù)/// </summary>/// <param name="entity">待添加數(shù)據(jù)</param>/// <returns>已添加數(shù)據(jù)</returns>public T AddEntity(T entity){entity = DbEntities.Set<T>().Add(entity);//DbEntities.SaveChanges();return entity;}} }

UserDal繼承BaseDal

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

數(shù)據(jù)訪問接口層的構(gòu)建

????? 然后我們建立相應(yīng)的IbaseDal接口和IUserDal接口，并且使UserDal類實現(xiàn)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實現(xiàn)IUserDal接口：

public partial class UserDal : BaseDal<User>,IUserDal

數(shù)據(jù)會話層的構(gòu)建

抽象工廠類AbstractFactory：

using System.Configuration; using System.Reflection; using PMS.IDAL;namespace PMS.DALFactory {public partial class AbstractFactory{//讀取保存在配置文件中的程序集名稱與命名空間名private static readonly string AssemblyPath = ConfigurationManager.AppSettings["AssemblyPath"];private static readonly string NameSpace = ConfigurationManager.AppSettings["NameSpace"];/// <summary>/// 獲取UserDal的實例/// </summary>/// <returns></returns>public static IUserDal CreateUserInfoDal(){var fullClassName = NameSpace + ".UserInfoDal";return CreateInstance(fullClassName) as IUserDal;}/// <summary>/// 通過反射獲得程序集中某類型的實例/// </summary>/// <param name="className"></param>/// <returns></returns>private static object CreateInstance(string className){var assembly = Assembly.Load(AssemblyPath);return assembly.CreateInstance(className);}} }

數(shù)據(jù)會話類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>/// 工作單元模式，統(tǒng)一保存數(shù)據(jù)/// </summary>/// <returns></returns>public bool SaveChanges(){return Db.SaveChanges() > 0;}} }

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業(yè)務(wù)邏輯層的構(gòu)建

業(yè)務(wù)類基類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();//子類一定要實現(xiàn)抽象方法，以指明當(dāng)前類的子類類型。 }/// <summary>/// 查詢過濾/// </summary>/// <param name="whereLambda"></param>/// <returns></returns>public IQueryable<T> LoadEntities(Expression<Func<T, bool>> whereLambda){return CurrentDal.LoadEntities(whereLambda);}/// <summary>/// 分頁/// </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>/// 刪除/// </summary>/// <param name="entity"></param>/// <returns></returns>public bool DeleteEntity(T entity){CurrentDal.DeleteEntity(entity);return CurrentDbSession.SaveChanges();}/// <summary>/// 編輯/// </summary>/// <param name="entity"></param>/// <returns></returns>public bool EditEntity(T entity){CurrentDal.EditEntity(entity);return CurrentDbSession.SaveChanges();}/// <summary>/// 添加數(shù)據(jù)/// </summary>/// <param name="entity"></param>/// <returns></returns>public T AddEntity(T entity){CurrentDal.AddEntity(entity);CurrentDbSession.SaveChanges();return entity;}} }

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UserService類：

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

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業(yè)務(wù)邏輯接口層的構(gòu)建

????? 直接建立對應(yīng)的接口并使用UserService類實現(xiàn)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類實現(xiàn)IUserService接口:

public partial class UserService : BaseService<User>, IUserService

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以上我們就完成了整個框架中關(guān)于User類的各層次的實現(xiàn)。

轉(zhuǎn)載于:https://www.cnblogs.com/WayneShao/p/5876880.html

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