.Net里的Attribute 学习

.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#