代理模式

            /*
             * 代理模式：
             * 代理类成为实际想调用对象的中间件，可以控制对实际调用对象的访问权限
             * 可以维护实际对象的引用
             */

1.代理类

namespace Data
{
    public interface IProxy
    {
        string InsertDB();
        string UpdateDB();
        string DelDB();
    }

    public class Proxy : IProxy
    {
        OperateDB operateDB;

        public Proxy()
        {
            operateDB = new OperateDB();
        }

        #region IProxy 成员

        public string InsertDB()
        {
            return operateDB.InsertDB();
        }

        public string UpdateDB()
        {
            return operateDB.UpdateDB();
        }

        public string DelDB()
        {
            return operateDB.DelDB();
        }

        #endregion
    }

    class OperateDB : IProxy
    {
        #region IProxy 成员

        public string InsertDB()
        {
            NorthwindEntities db = new NorthwindEntities();
            Employees e = new Employees();
            e.LastName = "chuanshi_yoyo_yoyo";
            e.FirstName = "zhushao";
            db.AddToEmployees(e);
            db.SaveChanges();
            return "添加数据成功\n";
        }

        public string UpdateDB()
        {
            NorthwindEntities db = new NorthwindEntities();
            Employees e = db.Employees.Where(c => c.EmployeeID == 43).FirstOrDefault();
            e.LastName = "yo_shao";
            db.SaveChanges();
            return "修改数据成功\n"; 
        }

        public string DelDB()
        {
            NorthwindEntities db = new NorthwindEntities();
            Employees e = db.Employees.Where(c => c.EmployeeID == 43).FirstOrDefault();
            db.DeleteObject(e);
            db.SaveChanges();
            return "删除数据成功\n";
        }

        #endregion
    }

}

2.调用类

            Proxy proxy = new Proxy();
            Console.WriteLine(proxy.InsertDB());
            Console.ReadKey();