在本文之前的前几篇浅谈.NET编译时注入（C#-->IL）、浅谈VS编译自定义编译任务—MSBuild Task(csproject)、编译时MSIL注入--实践Mono Cecil(1)已经讨论了MSBuild和Mono.Cicel。在这里我们将会利用它来实现一个简单的编译时AOP注入机制（这里所说的编译时是指c#到MSIL的预编译过程）。我更倾向于像EL（微软企业库框架）这类动态AOP。编译时AOP有PostSharp这种被称之为静态AOP框架，其优势在于直接代码语句，性能更好，它不需要我们多余的代码，像EL这种动态AOP，一般我们是不能直接new一个对象，需要容器（Container），在一些你的框架应用种，有时就需要使用者了解，再入我们对于WinForm、WebForm等.net平台上主流的基于微软事件机制的框架，事件方法的截获，往往我们需要改变、包装。在这时静态AOP就显出了他的优势。
Class Diagram：
1：IMethodInject：Interface，拥有Executeing，Exceptioned，ExecuteSuccess三个契约为别为执行前，异常，成功。它们都有公同的参数类型：MethodExecutionEventArgs
Executeing：返回值为bool类型，将决定是否继续执行方法体。Exceptioned：属性Eeption代表发生的异常信息，返回值ExceptionStrategy（取值：Handle, ReThrow, ThrowNew）决定异常处理机制，Handle已处理并忽略，ReThrow重新抛出，ThrowNew抛出一个包装后的来源于MethodExecutionEventArgs 的Exception。ExecuteSuccess，对于拥有返回值的方法，可以修改MethodExecutionEventArgs 的ReturnValue，修改返回值。最后MethodExecutionEventArgs的Order决定多个Attribute的注入先后，即方法截获的先后顺序。
1：MethodInterceptBase：针对于方法Attribute标签，实现方法截获View Code
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[AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)] public class MethodInterceptBase : Attribute, IMethodInject { public int Order { get; set; } #region IMethodInject Members public virtual bool Executeing(MethodExecutionEventArgs args) { return true; } public virtual ExceptionStrategy Exceptioned(MethodExecutionEventArgs args) { return ExceptionStrategy.ReThrow; } public virtual void ExecuteSuccess(MethodExecutionEventArgs args) { } #endregion } 复制代码 2：
View Code [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)] public class MatchedMethodInterceptBase : Attribute, IMethodInject { public int Order { get; set; } public string Rule { get; set; } #region IMethodInject Members public virtual bool Executeing(MethodExecutionEventArgs args) { return true; } public virtual ExceptionStrategy Exceptioned(MethodExecutionEventArgs args) { return ExceptionStrategy.ReThrow; } public virtual void ExecuteSuccess(MethodExecutionEventArgs args) { } #endregion } 复制代码 3：PropertyInterceptBase：实现属性的注入，其属性Action（enum PropertyInterceptAction：None Get, Set）指注入属性的get或者Set；View Code
下面是一个简单测试Code：
View Code using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Reflection; using Green.AOP; namespace Test { // [TestAOP2Attribute(Rule = "TestMethod1*")] public class Class1 { // [TestAOPPropertyAttribute(Action = PropertyInterceptAction.Set)] [TestAOPPropertyGetAttribute(Action = PropertyInterceptAction.Get)] public testStrust TestProperty { get; set; } [Obsolete()] public static void Main(string[] args) { try { var y = new Class1(); // y.TestProperty = DateTime.Now; Console.WriteLine(y.TestProperty); } catch (Exception ex) { Console.WriteLine(ex.ToString()); } // new Class1().TestMethod1(1, 2, null); Console.Read(); //throw new Exception("exfffffffffffffffffffff"); } //[TestAOPAttribute(Order=1)] //[TestAOP1Attribute(TestProperty = 1, Template = "sdsdsd",Order=0)] public Class1 TestMethod1(int i, int j, Class1 c) { Console.WriteLine("ok"); return new Class1(); } } public class TestAOPPropertyGetAttribute : Green.AOP.PropertyInterceptBase { #region IMethodInject Members public override bool Executeing(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine("------------------" + args); Console.WriteLine(args.Instance); Console.WriteLine(args.Method); Console.WriteLine(this.GetType() + ":" + "Executeing"); return true; } public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Exceptioned"); return Green.AOP.ExceptionStrategy.ReThrow; } public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine("-----------"); Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess" + "--result:" + args.ReturnValue); } #endregion } public class TestAOPPropertyAttribute : Green.AOP.PropertyInterceptBase { #region IMethodInject Members public override bool Executeing(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(args.Instance); Console.WriteLine(args.Method); Console.WriteLine(this.GetType() + ":" + "Executeing"); return true; } public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Exceptioned"); return Green.AOP.ExceptionStrategy.Handle; } public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess"); } #endregion } public class TestAOP2Attribute : Green.AOP.MatchedMethodInterceptBase { #region IMethodInject Members public override bool Executeing(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(args.Instance); Console.WriteLine(args.Method); Console.WriteLine(this.GetType() + ":" + "Executeing"); return true; } public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Exceptioned"); return Green.AOP.ExceptionStrategy.Handle; } public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess"); } #endregion #region IMethodInject Members public bool Match(System.Reflection.MethodBase method) { return true; } #endregion } //[AttributeUsage(AttributeTargets.Method)] public class TestAOPAttribute : Green.AOP.MethodInterceptBase { #region IMethodInject Members public override bool Executeing(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Executeing"); return true; } public override Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Exceptioned"); return Green.AOP.ExceptionStrategy.Handle; } public override void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess"); } #endregion #region IMethodInject Members public bool Match(System.Reflection.MethodBase method) { return true; } #endregion } [AttributeUsage(AttributeTargets.Method)] public class TestAOP1Attribute : Attribute, Green.AOP.IMethodInject { public int Order { get; set; } public int TestProperty { get; set; } public string Template { get; set; } #region IMethodInject Members public bool Executeing(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Executeing"); return true; } public Green.AOP.ExceptionStrategy Exceptioned(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "Exceptioned"); return Green.AOP.ExceptionStrategy.Handle; } public void ExecuteSuccess(Green.AOP.MethodExecutionEventArgs args) { Console.WriteLine(this.GetType() + ":" + "ExecuteSuccess"); } #endregion #region IMethodInject Members public bool Match(System.Reflection.MethodBase method) { return true; } #endregion } } 复制代码 注意测试有两种方式（由于没有安装包）：
1：先重编译测试项目，运行ConsoleApplication2（在属性中修改控制台其实参数）。在查看测试项目。
2：将项目ConsoleApplication2修改为类库，在添加修改csprojec信息，Task位于Green.AOP.MyBuildTask，具体可以参见上一篇浅谈VS编译自定义编译任务—MSBuild Task(csproject)。
在后续将会从简单Demo分析实现原理。
[AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)] public class PropertyInterceptBase : Attribute, IMethodInject { public PropertyInterceptAction Action { get; set; } public int Order { get; set; } #region IMethodInject Members public virtual bool Executeing(MethodExecutionEventArgs args) { return true; } public virtual ExceptionStrategy Exceptioned(MethodExecutionEventArgs args) { return ExceptionStrategy.ReThrow; } public virtual void ExecuteSuccess(MethodExecutionEventArgs args) { } #endregion } 复制代码 亿速云「云服务器」，即开即用、新一代英特尔至强铂金CPU、三副本存储NVMe SSD云盘，价格低至29元/月。点击查看>>
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