之前实现了NetCore实现自定义IOC容器注入，在Controller使用事物的过程中思考是否能够像Spring一样通过自定义注解实现事物管理，思路图如下

事物的动作拆分只需要根据当前执行线程划分Connection对象并开启事物即可，重点是在Emit代码织入过程中对异常捕捉的处理

处理过程中主要会用到BeginExceptionBlock开启try代码块，BeginCatchBlock开启catch代码块，EndExceptionBlock结束异常捕捉代码块

创建事物注解Transitional用来标记Controller中需要事物执行的方法

    [AttributeUsage(AttributeTargets.Method)]public class Transitional : System.Attribute{public bool AutoRollBack { set; get; }public Transitional(){AutoRollBack = true;}}

Emit编织时需要注意异常捕捉时有返回值时建立全局变量返回，执行事物管理器类的静态方法直接使用call，例如 ilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("DoRollBack"))，同时Controller被拦截的方法需要标记Transitional注解且同时是虚方法

被代理类示例

public class TransitionalMovie{[Transitional]public virtual void Test1(){Console.WriteLine("Test1");}[Transitional]public virtual string Test2(){Console.WriteLine("Test2");throw new Exception("111");return "Hello";}[Transitional(AutoRollBack = false)]public virtual void Test3(string Key){Console.WriteLine("Test3");Console.WriteLine(Key);}

IOC使用示例，IOC容器原理可参考c#通过Emit方式实现动态代理

 var container = new ContainerBuilder();container.RegisterType<TransitionalMovie>().EnableIntercept();container.Build();TransitionalMovie tm = container.Resolve<TransitionalMovie>();tm.Test1();string result = tm.Test2();Console.WriteLine(result);tm.Test3("世界第一等");

动态代理生成类反编译代码

动态代理包含异常拦截与事物的全部代码

 public static Object CreateProxyObject(Type InterfaceType, Type ImpType, Type InterceptType, bool inheritMode = true, bool isInterceptAllMethod = true){string nameOfAssembly = ImpType.Name + "ProxyAssembly";string nameOfModule = ImpType.Name + "ProxyModule";string nameOfType = ImpType.Name + "Proxy";var assemblyName = new AssemblyName(nameOfAssembly);ModuleBuilder moduleBuilder = null;var assembly = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);moduleBuilder = assembly.DefineDynamicModule(nameOfModule);TypeBuilder typeBuilder;if (inheritMode){typeBuilder = moduleBuilder.DefineType(nameOfType, TypeAttributes.Public, ImpType);}else{typeBuilder = moduleBuilder.DefineType(nameOfType, TypeAttributes.Public, null, new[] { InterfaceType });}InjectInterceptor(typeBuilder, ImpType, InterceptType, inheritMode, isInterceptAllMethod);var t = typeBuilder.CreateType();return Activator.CreateInstance(t);}private static void InjectInterceptor(TypeBuilder typeBuilder, Type ImpType, Type InterceptType, bool inheritMode, bool isInterceptAllMethod){#region 变量定义// ---- 变量定义 ----var constructorBuilder = typeBuilder.DefineConstructor(MethodAttributes.Public, CallingConventions.Standard, null);var ilOfCtor = constructorBuilder.GetILGenerator();//---- 拦截类对象定义 ----if (InterceptType == null){InterceptType = typeof(DefaultIntercept);}//声明var fieldInterceptor = typeBuilder.DefineField("_interceptor", InterceptType, FieldAttributes.Private);//赋值ilOfCtor.Emit(OpCodes.Ldarg_0);ilOfCtor.Emit(OpCodes.Newobj, InterceptType.GetConstructor(new Type[0]));ilOfCtor.Emit(OpCodes.Stfld, fieldInterceptor);#endregion#region 代理对象定义//---- 实现类对象定义 ----//声明var fieldBeProxy = typeBuilder.DefineField("_beproxy", ImpType, FieldAttributes.Private);//赋值ilOfCtor.Emit(OpCodes.Ldarg_0);ilOfCtor.Emit(OpCodes.Newobj, ImpType.GetConstructor(new Type[0]));ilOfCtor.Emit(OpCodes.Stfld, fieldBeProxy);ilOfCtor.Emit(OpCodes.Ret);#endregion// ---- 定义类中的方法 ----var methodsOfType = ImpType.GetMethods(BindingFlags.Public | BindingFlags.Instance).Where(a => a.IsVirtual).ToArray();string[] ignoreMethodName = new[] { "GetType", "ToString", "GetHashCode", "Equals" };for (var i = 0; i < methodsOfType.Length; i++){#region 方法是否需要拦截判断，Object内置方法过滤bool IsMethodIntercept = false;bool IsTransitinal = false;var method = methodsOfType[i];//---- 过滤Object基类方法,如果是继承，基类中的属性get，set方法也要过滤 ----if (ignoreMethodName.Contains(method.Name) || method.Name.StartsWith("set_") || method.Name.StartsWith("get_")){continue;}// ---- 判断方法是否需要拦截 ----if (isInterceptAllMethod){if (method.GetCustomAttribute(typeof(IgnoreInterceptAttibute)) == null){IsMethodIntercept = true;}}else{if (method.GetCustomAttribute(typeof(InterceptAttibute)) != null){IsMethodIntercept = true;}}// ---- 判断方法是否需要纳入事物管理中 ----if (method.GetCustomAttribute(typeof(Transitional)) != null){IsTransitinal = true;}#endregion#region 泛型方法处理var methodParameterTypes =method.GetParameters().Select(p => p.ParameterType).ToArray();// ---- 定义方法名与参数 ----var methodBuilder = typeBuilder.DefineMethod(method.Name,MethodAttributes.Public | MethodAttributes.Virtual,CallingConventions.Standard,method.ReturnType,methodParameterTypes);//如果是泛型方法if (method.IsGenericMethod){//获取所有泛型参数类型定义Type[] Args = method.GetGenericArguments();List<string> GenericArgNames = new List<string>();for (int j = 0; j < Args.Length; j++){GenericArgNames.Add(Args[j].Name);}//代理类方法生成泛型参数定义GenericTypeParameterBuilder[] DGP = methodBuilder.DefineGenericParameters(GenericArgNames.ToArray());//泛型参数约束设置for (int j = 0; j < DGP.Length; j++){//泛型参数继承约束DGP[j].SetBaseTypeConstraint(Args[j].BaseType);//泛型参数完成接口约束DGP[j].SetInterfaceConstraints(Args[j].GetInterfaces());}}#endregionvar ilOfMethod = methodBuilder.GetILGenerator();var methodresult = ilOfMethod.DeclareLocal(typeof(object));  //instance of result//赋值方法结果对象初始值为nullilOfMethod.Emit(OpCodes.Ldnull);ilOfMethod.Emit(OpCodes.Stloc_0);#region 事物拦截开始if (IsTransitinal){//开始try模块ilOfMethod.BeginExceptionBlock();//调用TransitionManage.StartTransitionilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("StartTransition"));ilOfMethod.Emit(OpCodes.Ldarg_0);}#endregion#region before拦截// ---- before ----if (IsMethodIntercept){var parameters = ilOfMethod.DeclareLocal(typeof(object[]));ilOfMethod.Emit(OpCodes.Ldc_I4, methodParameterTypes.Length);ilOfMethod.Emit(OpCodes.Newarr, typeof(object));ilOfMethod.Emit(OpCodes.Stloc, parameters);for (var j = 0; j < methodParameterTypes.Length; j++){ilOfMethod.Emit(OpCodes.Ldloc, parameters);ilOfMethod.Emit(OpCodes.Ldc_I4, j);ilOfMethod.Emit(OpCodes.Ldarg, j + 1);ilOfMethod.Emit(OpCodes.Stelem_Ref);}ilOfMethod.Emit(OpCodes.Ldarg_0);ilOfMethod.Emit(OpCodes.Ldfld, fieldInterceptor);//拦截方法参数赋值if (inheritMode){//继承传递代理类本身ilOfMethod.Emit(OpCodes.Ldarg_0);}else{//接口传递实现类ilOfMethod.Emit(OpCodes.Ldarg_0);ilOfMethod.Emit(OpCodes.Ldfld, fieldBeProxy);}ilOfMethod.Emit(OpCodes.Ldstr, method.Name);ilOfMethod.Emit(OpCodes.Ldloc, parameters);//调用拦截类中的Before方法ilOfMethod.Emit(OpCodes.Callvirt, InterceptType.GetMethod("Before"));}#endregion#region 方法执行// ---- call ----////定义实现类局部变量//var localimpobj = ilOfMethod.DeclareLocal(ImpType);////new一个实现类的对象//ilOfMethod.Emit(OpCodes.Newobj, ImpType.GetConstructor(new Type[0]));////局部变量赋值//ilOfMethod.Emit(OpCodes.Stloc, localimpobj);////局部变量出栈，等待调用//ilOfMethod.Emit(OpCodes.Ldloc, localimpobj);//方法执行开始时间var localstart = ilOfMethod.DeclareLocal(typeof(DateTime));ilOfMethod.Emit(OpCodes.Call, typeof(DateTime).GetMethod("get_Now"));ilOfMethod.Emit(OpCodes.Stloc, localstart);if (inheritMode){//继承方法调用父类的方法ilOfMethod.Emit(OpCodes.Ldarg_0);for (var j = 0; j < methodParameterTypes.Length; j++){ilOfMethod.Emit(OpCodes.Ldarg, j + 1);}ilOfMethod.Emit(OpCodes.Call, ImpType.GetMethod(method.Name));}else{//接口方法调用实现类的方法ilOfMethod.Emit(OpCodes.Ldarg_0);ilOfMethod.Emit(OpCodes.Ldfld, fieldBeProxy);for (var j = 0; j < methodParameterTypes.Length; j++){ilOfMethod.Emit(OpCodes.Ldarg, j + 1);}//调用方法ilOfMethod.Emit(OpCodes.Callvirt, ImpType.GetMethod(method.Name));}var localend = ilOfMethod.DeclareLocal(typeof(DateTime));ilOfMethod.Emit(OpCodes.Call, typeof(DateTime).GetMethod("get_Now"));ilOfMethod.Emit(OpCodes.Stloc, localend);#endregion#region after拦截// ---- after ----if (IsMethodIntercept){if (method.ReturnType == typeof(void)){ilOfMethod.Emit(OpCodes.Ldnull);}else{ilOfMethod.Emit(OpCodes.Box, method.ReturnType);}ilOfMethod.Emit(OpCodes.Stloc, methodresult);ilOfMethod.Emit(OpCodes.Ldarg_0);ilOfMethod.Emit(OpCodes.Ldfld, fieldInterceptor);//拦截方法参数赋值if (inheritMode){//继承传递代理类本身ilOfMethod.Emit(OpCodes.Ldarg_0);}else{//接口传递实现类ilOfMethod.Emit(OpCodes.Ldarg_0);ilOfMethod.Emit(OpCodes.Ldfld, fieldBeProxy);}ilOfMethod.Emit(OpCodes.Ldstr, method.Name);ilOfMethod.Emit(OpCodes.Ldloc, methodresult);ilOfMethod.Emit(OpCodes.Ldloc, localstart);ilOfMethod.Emit(OpCodes.Ldloc, localend);ilOfMethod.Emit(OpCodes.Callvirt, InterceptType.GetMethod("After"));}#endregion#region 事物提交及异常捕获及回滚if (IsTransitinal){//调用TransitionManage.DoCommitilOfMethod.Emit(OpCodes.Pop);ilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("DoCommit"));ilOfMethod.Emit(OpCodes.Ldarg_0);//开始catch模块ilOfMethod.BeginCatchBlock(typeof(System.Exception));//调用TransitionManage.DoRollBackTransitional transition = (Transitional)method.GetCustomAttribute(typeof(Transitional));if (transition.AutoRollBack){ilOfMethod.Emit(OpCodes.Pop);ilOfMethod.Emit(OpCodes.Call, typeof(TransitionManage).GetMethod("DoRollBack"));}else{//throw异常ilOfMethod.Emit(OpCodes.Pop);ilOfMethod.Emit(OpCodes.Rethrow);}//结束异常块ilOfMethod.EndExceptionBlock();}#endregion#region 处理返回值//调用完After方法后,将实现类的方法返回值的临时变量再次压栈用作代理方法的返回ilOfMethod.Emit(OpCodes.Ldloc, methodresult);// pop the stack if return voidif (method.ReturnType == typeof(void)){ilOfMethod.Emit(OpCodes.Pop);}else{if (method.ReturnType.IsValueType){ilOfMethod.Emit(OpCodes.Unbox_Any, method.ReturnType);}else{ilOfMethod.Emit(OpCodes.Castclass, method.ReturnType);}}#endregion// completeilOfMethod.Emit(OpCodes.Ret);}}