.Net里的Attribute 学习

前两天看到书里边讲Attribute定制，结合了网上的资料，自己做了简单的登录功能，并结合了某些设计模式，有兴趣的朋友可以看下。由于时间原因，没有做过多的说明，直接上代码，希望能帮助哪些不会的初学者，同时也希望得到高人的指点，本人将虚心接受批评，谢谢!

用户登录操作类：

using System;

using LemonFreamworkAOP.User;

using LemonFreamworkAOP.AOP;

namespace LemonFreamworkAOP.User

{

    [LoginAOP]

    public class UserDAL : ContextBoundObject, IUser

    {

        private UserInfo userInfo;

        public UserDAL(UserInfo userInfo)

        {

            this.userInfo = userInfo;

        }

        public Boolean IsLogin(UserInfo user)

        {

            return this.userInfo == user;

        }

    }

}

下边是几个核心抽象基类类：

 AOPProperty

using System;

using System.Runtime.Remoting.Activation;

using System.Runtime.Remoting.Contexts;

using System.Runtime.Remoting.Messaging;

namespace LemonFreamworkAOP.AOP

{

    public abstract class AOPProperty : IContextProperty, IContributeObjectSink

    {

        protected virtual String GetName

        {

            get { return "AOP"; }

        }

        protected virtual Boolean IsOK(Context newCtx)

        {

            return true;

        }

        protected abstract IMessageSink GetSink(IMessageSink nextSink);

        #region IContextProperty IContributeObjectSink

        public void Freeze(Context newContext)

        {

        }

        public Boolean IsNewContextOK(Context newCtx)

        {

            return IsOK(newCtx);

        }

        public String Name

        {

            get { return GetName; }

        }

        public IMessageSink GetObjectSink(MarshalByRefObject obj, IMessageSink nextSink)

        {

            return GetSink(nextSink);

        }

        #endregion

    }

}

 AOPAttribute

using System;

using System.Runtime.Remoting.Activation;

using System.Runtime.Remoting.Contexts;

using System.Runtime.Remoting.Messaging;

namespace LemonFreamworkAOP.AOP

{

    public abstract class AOPAttribute : ContextAttribute

    {

        public AOPAttribute() : base("AOP") { }

        public sealed override void GetPropertiesForNewContext(IConstructionCallMessage ctorMsg)

        {

            ctorMsg.ContextProperties.Add(CreateAOPProperty());

        }

        protected abstract AOPProperty CreateAOPProperty();

    }

}

 AOPSink

using System;

using System.Collections.Generic;

using LemonFreamworkAOP.User;

using System.Runtime.Remoting.Activation;

using System.Runtime.Remoting.Contexts;

using System.Runtime.Remoting.Messaging;

namespace LemonFreamworkAOP.AOP

{

    public abstract class AOPSink : IMessageSink

    {

        private Dictionary<String, Object> beforeHandles;

        private Dictionary<String, Object> afterHandler;

        private IMessageSink messageSink;

        protected const String errorDesc = "Not Find MethodName !";

        public AOPSink(IMessageSink messageSink)

        {

            this.beforeHandles = new Dictionary<String, Object>();

            this.afterHandler = new Dictionary<String, Object>();

            this.messageSink = messageSink;

            AddAllBeforeAOPHandle();

            AddAllAfterAOPHandle();

        }

        public virtual void AddBeforeAOPHandle(String methodName, BeforeAOPHandle beforeHandle)

        {

            if (String.IsNullOrEmpty(methodName)) return;

            if (!beforeHandles.ContainsKey(methodName))

                beforeHandles.Add(methodName, beforeHandle);

        }

        public virtual void AddAfterAOPHandle(String methodName, AfterAOPHandle aftereHandle)

        {

            if (String.IsNullOrEmpty(methodName)) return;

            if (!afterHandler.ContainsKey(methodName))

                afterHandler.Add(methodName, aftereHandle);

        }

        public virtual BeforeAOPHandle FindBeforeAOPHandle(String methodName)

        {

            if (beforeHandles.ContainsKey(methodName))

                return beforeHandles[methodName] as BeforeAOPHandle;

            else

                throw new Exception(errorDesc);

        }

        public virtual AfterAOPHandle FindAfterAOPHandle(String methodName)

        {

            if (afterHandler.ContainsKey(methodName))

                return beforeHandles[methodName] as AfterAOPHandle;

            else

                throw new Exception(errorDesc);

        }

        public IMessageCtrl AsyncProcessMessage(IMessage msg, IMessageSink replySink)

        {

            return null;

        }

        public IMessageSink NextSink

        {

            get { return this.messageSink; }

        }

        public IMessage SyncProcessMessage(IMessage msg)

        {

            IMethodCallMessage callMsg = msg as IMethodCallMessage;

            BeforeProcess(callMsg);

            IMessage imsg = messageSink.SyncProcessMessage(msg);

            //IMethodReturnMessage retMsg = imsg as IMethodReturnMessage;

            //AfterProcess(callMsg.MethodName, retMsg);

            return imsg;

        }

        protected abstract void AddAllBeforeAOPHandle();

        protected abstract void AddAllAfterAOPHandle();

        protected virtual void BeforeProcess(IMethodCallMessage callMsg)

        {

            String methodName = callMsg.MethodName;

            BeforeAOPHandle beforeHandle = FindBeforeAOPHandle(methodName);

            if (beforeHandle != null)

                beforeHandle(callMsg);

        }

        protected virtual void AfterProcess(String methodName, IMethodReturnMessage retMsg)

        {

            AfterAOPHandle afterHandle = FindAfterAOPHandle(methodName);

            if (afterHandle != null)

                afterHandle(retMsg);

        }

    }

}

以下是登录功能的派生子类

 LoginAOPAttribute

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace LemonFreamworkAOP.AOP

{

    [AttributeUsage(AttributeTargets.Class)]

    public class LoginAOPAttribute : AOPAttribute

    {

        protected override AOPProperty CreateAOPProperty()

        {

            return new LoginAOPProperty();

        }

    }

}

 LoginAOPProperty

using System;

using System.Runtime.Remoting.Activation;

using System.Runtime.Remoting.Contexts;

using System.Runtime.Remoting.Messaging;

namespace LemonFreamworkAOP.AOP

{

    public class LoginAOPProperty : AOPProperty

    {

        protected override IMessageSink GetSink(IMessageSink nextSink)

        {

            return new LoginAOPSink(nextSink);

        }

    }

}

 LoginAOPSink

using System;

using LemonFreamworkAOP.User;

using LemonFreamworkAOP.Untity;

using System.Runtime.Remoting.Activation;

using System.Runtime.Remoting.Contexts;

using System.Runtime.Remoting.Messaging;

namespace LemonFreamworkAOP.AOP

{

    public class LoginAOPSink : AOPSink

    {

        public LoginAOPSink(IMessageSink messageSink) : base(messageSink) { }

        public void BeforeUserLogin(IMethodCallMessage callMsg)

        {

            UserInfo loginUser = callMsg.GetArg(0) as UserInfo;

            UserInfo configUser = ConfigHelper.GetUser;

            if (loginUser.UserName != configUser.UserName || loginUser.Password != configUser.Password)

                throw new Exception("用户名或密码不正确!");

        }

        protected override void AddAllBeforeAOPHandle()

        {

            AddBeforeAOPHandle("IsLogin", BeforeUserLogin);

        }

        protected override void AddAllAfterAOPHandle()

        {

        }

    }

}

 

 

分类: CLR Via C#