.NET C#三层开发结构Demo详解及源码（二）

IBLL业务逻辑接口描述，需引用Model和IDAL，包含一个BLL工厂类，业务逻辑基础接口，两个模块逻辑接口

BLLFactory.cs 业务逻辑工厂类代码

using Model;
using System.Configuration;
using System.Reflection;

namespace IBLL
{
    /// <summary>
    /// 业务逻辑工厂类
    /// </summary>
    /// <typeparam name="T">需要操作的业务逻辑类Model实体类型</typeparam>
    public class BLLFactory<T>
    {
        private static readonly string BLL_NameSpace = ConfigurationManager.AppSettings["BLL_NameSpace"];
        private static readonly string BLL_Users = ConfigurationManager.AppSettings["BLL_Users"];
        private static readonly string BLL_Nation = ConfigurationManager.AppSettings["BLL_Nation"];

        /// <summary>
        /// 返回此泛型Model对应的BLL 
        /// </summary>
        /// <returns></returns>
        public dynamic CreateBLL()
        {
            if (typeof(T) == typeof(Users))
                return Assembly.Load(BLL_NameSpace).CreateInstance(BLL_NameSpace + "." + BLL_Users) as IUsersIBLL;
            else if (typeof(T) == typeof(Nation))
                return Assembly.Load(BLL_NameSpace).CreateInstance(BLL_NameSpace + "." + BLL_Nation) as INationIBLL;

            return null;
        }
    }
}

IBaseIBLL.cs 业务逻辑基础接口描述

using System;
using System.Linq;
using System.Linq.Expressions;

namespace IBLL
{
    /// <summary>
    /// 业务逻辑基础描述接口
    /// </summary>
    public interface IBaseIBLL<T>
    {
        IQueryable<T> Get();

        IQueryable<T> Get(Expression<Func<T, bool>> exp);

        T Get(int id);

        int Add(T entity);

        int Change(T entity);

        int Remove(int id);
    }
}

IUsersIBLL.cs 和 INationIBLL.cs 业务模块接口

using System.Linq;
using Model;

namespace IBLL
{
    /// <summary>
    /// Users业务逻辑描述接口
    /// </summary>
    public interface IUsersIBLL : IBaseIBLL<Users>
    {
        /// <summary>
        /// 扩展分页方法描述
        /// </summary>
        /// <param name="pageSize"></param>
        /// <param name="pageIndex"></param>
        /// <returns></returns>
        IQueryable<Users> Get(int pageSize, int pageIndex);
    }
}

using Model;

namespace IBLL
{
    /// <summary>
    /// Nation业务逻辑描述接口
    /// </summary>
    public interface INationIBLL : IBaseIBLL<Nation>
    {
    }
}

接下来就是TestBLL业务逻辑接口实现，里面会有TestDAL的调用，包含基础接口实现，模块功能实现

BaseBLL.cs 基础接口实现代码

using System;
using System.Linq;
using System.Linq.Expressions;
using IBLL;
using IDAL;

namespace TestBLL
{
    /// <summary>
    /// 业务逻辑基础接口实现
    /// </summary>
    public class BaseBLL<T> : IBaseIBLL<T> where T : class
    {
        /// 注意，这里需要子类来实例化所需要的数据访问类，构造函数中指定
        private IBaseIDAL<T> _Dal;

        //构造
        public BaseBLL(IBaseIDAL<T> dal) { _Dal = dal; }

        public int Add(T entity)
        {
            return _Dal.Insert(entity);
        }

        public int Change(T entity)
        {
            return _Dal.Update(entity);
        }

        public IQueryable<T> Get()
        {
            return _Dal.Select();
        }

        public T Get(int id)
        {
            return _Dal.Select(id);
        }

        public IQueryable<T> Get(Expression<Func<T, bool>> exp)
        {
            return _Dal.Select(exp);
        }

        public int Remove(int id)
        {
            T t = _Dal.Select(id);
            if (t != null) return _Dal.Delete(t);
            return 0;
        }
    }
}

UsersBLL.cs 和 NationBLL.cs两个模块实现类

using System.Linq;
using Model;
using IDAL;
using IBLL;

namespace TestBLL
{
    /// <summary>
    /// Users业务逻辑实现
    /// </summary>
    public class UsersBLL : BaseBLL<Users>, IUsersIBLL
    {
        private static IUsersIDAL dal = new DALFactory<Users>().CreateDAL();

        //构造函数中将具体的数据访问对象传到父级的构造函数中
        public UsersBLL() : base(dal)
        {
        }

        public IQueryable<Users> Get(int pageSize, int pageIndex)
        {
            return dal.Select(pageSize, pageIndex);
        }
    }
}

using Model;
using IDAL;
using IBLL;

namespace TestBLL
{
    /// <summary>
    /// Nation业务逻辑实现
    /// </summary>
    public class NationBLL : BaseBLL<Nation>, INationIBLL
    {
        private static INationIDAL dal = new DALFactory<Nation>().CreateDAL();
        public NationBLL() : base(dal)
        {
        }
    }
}

接下来就是WebUI表现层了，只需要引用IBLL和Model即可，通过BLLFactory工厂类创建相应的操作对象，大大简化UI层的代码，结果是这样的：

前端就使用了一个Repeater，C#代码如下

using System;
using System.Linq;
using System.Web.UI.WebControls;
using IBLL;
using Model;

namespace WebUI
{
    public partial class page1 : System.Web.UI.Page
    {
        //通过业务逻辑层工厂创建相应的操作对象
        IUsersIBLL userBLL = new BLLFactory<Users>().CreateBLL();
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                //调用对象方法
                Repeater1.DataSource = userBLL.Get().ToList();
                Repeater1.DataBind();
            }
        }
    }
}

结束！

语言组织能力有限，想的很多却写不出来，以后有机会慢慢完善吧。