Question

使用 TypeGenerator 类

   public class TypeGenerator
    {
        /// <summary>
        /// internal cache for already generated types
        /// </summary>
        private static Dictionary<Type, Type> asyncTypeCache = new Dictionary<Type, Type>();      

        /// <summary>
        /// provides a cache for the modules
        /// </summary>
        private static Dictionary<string, ModuleBuilder> moduleBuilderCache = new Dictionary<string, ModuleBuilder>();

        /// <summary>
        /// Generates the Async version of the TSync type.
        /// the generate type repects the AsyncPattern and it is already decorated with attributes for WCF operations
        /// </summary>
        /// <typeparam name="TSync">The Sync version of type</typeparam>
        /// <returns>A type that is the Async version of the TSync type, that implements the AsyncPattern for WCF</returns>
        public Type GenerateAsyncInterfaceFor<TSync>() where TSync : class
        {
            Type syncType = typeof(TSync);

            if (asyncTypeCache.ContainsKey(syncType)) return asyncTypeCache[syncType];

            if (!syncType.IsInterface) throw new InvalidOperationException("Only interface type could be transformed");

            var asynchAssemblyName = string.Format("{0}.Async", syncType.Namespace);

            TypeBuilder typeBuilder =
                GetModuleBuilder(asynchAssemblyName)
                .DefineType(
                    string.Format("{0}.Async.{1}", syncType.Namespace, syncType.Name),
                    (syncType.IsPublic ? TypeAttributes.Public : 0) |
                    TypeAttributes.Abstract |
                    TypeAttributes.Interface);

            foreach (var method in syncType.GetAllInterfaceMethods())
            {
                AddBeginAsynchVersionForMethod(typeBuilder, method, @"http://tempuri.org");
                AddEndAsynchVersionForMethod(typeBuilder, method);
            }

            var serviceContractConstructor = typeof(ServiceContractAttribute).GetConstructor(new Type[0]);
            var attribuiteBuilder =
                new CustomAttributeBuilder(
                    serviceContractConstructor,
                    new object[0]);

            typeBuilder.SetCustomAttribute(attribuiteBuilder);

            Type asyncType = typeBuilder.CreateType();

            asyncTypeCache.Add(syncType, asyncType);
            return asyncType;
        }

        /// <summary>
        /// Creates a End verison of a sync method, that implements the AsyncPattern
        /// </summary>
        /// <param name="typeBuilder">the tipebuilder where the type is being building</param>
        /// <param name="method">information about the sync version of the method</param>
        private void AddEndAsynchVersionForMethod(TypeBuilder typeBuilder, MethodInfo method)
        {
            string endMethodName = string.Format("End{0}", method.Name);

            var parameters =
                method.GetParameters()
                .Select(x =>
                    new
                    {
                        Type = x.ParameterType,
                        Name = x.Name,
                        Attributes = x.Attributes,
                    })
                .ToList();

            parameters.Add(
                new
                {
                    Type = typeof(IAsyncResult),
                    Name = "asyncResult",
                    Attributes = ParameterAttributes.None,
                });

            var methodBuilder =
                typeBuilder
                .DefineMethod(
                    endMethodName,
                    method.Attributes,
                    method.CallingConvention,
                    method.ReturnType,
                    parameters.Select(x => x.Type).ToArray());

            for (int i = 0; i < parameters.Count(); i++)
            {
                var parameter = parameters[i];
                methodBuilder.DefineParameter(i + 1, parameter.Attributes, parameter.Name);             
            }
        }

        /// <summary>
        /// Creates a Begin verison of a sync method, that implements the AsyncPattern
        /// </summary>
        /// <param name="typeBuilder">the tipebuilder where the type is being building</param>
        /// <param name="method">information about the sync version of the method</param>
        private void AddBeginAsynchVersionForMethod(TypeBuilder typeBuilder, MethodInfo method, string nameSpace)
        {
            string beginMethodName = string.Format("Begin{0}", method.Name);

            var parametersTypeList = method.GetParameters().Select(x => x.ParameterType).ToList();
            var parametersNameList = method.GetParameters().Select(x => x.Name).ToList();
            var parametersAttributeList = method.GetParameters().Select(x => x.Attributes).ToList();

            parametersTypeList.Add(typeof(AsyncCallback));
            parametersAttributeList.Add(ParameterAttributes.None);
            parametersNameList.Add("callBack");

            parametersTypeList.Add(typeof(object));
            parametersAttributeList.Add(ParameterAttributes.None);
            parametersNameList.Add("statusObject");

            var methodBuilder = 
                typeBuilder
                .DefineMethod(
                    beginMethodName,
                    method.Attributes,
                    method.CallingConvention,
                    typeof(IAsyncResult),
                    parametersTypeList.ToArray());

            for (int i = 0; i < parametersTypeList.Count(); i++)
            {
                methodBuilder.DefineParameter(i + 1, parametersAttributeList[i], parametersNameList[i]);
            }

            var operationContractConstructor = typeof(OperationContractAttribute).GetConstructor(new Type[0]);
            var asynchPatternProperty = typeof(OperationContractAttribute).GetProperty("AsyncPattern");

            var actionProperty = typeof(OperationContractAttribute).GetProperty("Action");
            var actionValue = string.Format("{0}/{1}/{2}", nameSpace, method.DeclaringType.Name, method.Name);

            var replyActionProperty = typeof(OperationContractAttribute).GetProperty("ReplyAction");
            var replyActionValue = string.Format("{0}/{1}/{2}Response", nameSpace, method.DeclaringType.Name, method.Name);

            var attribuiteBuilder = 
                new CustomAttributeBuilder(
                    operationContractConstructor, 
                    new object[0],
                    new[] { asynchPatternProperty, actionProperty, replyActionProperty },
                    new object[] { true, actionValue, replyActionValue });



            methodBuilder.SetCustomAttribute(attribuiteBuilder);
        }

        /// <summary>
        /// provides a ModelBuilder with the required assembly name
        /// </summary>
        /// <param name="requiredAssemblyName">the assembly name for where the type will be generated in</param>
        /// <returns>a model builder</returns>
        /// <remarks>in this version the model builder is not cached, it could be interesting to generate all the types in the same assembly by caching the model builder</remarks>
        private ModuleBuilder GetModuleBuilder(string requiredAssemblyName)
        {
            if (moduleBuilderCache.ContainsKey(requiredAssemblyName))
            {
                return moduleBuilderCache[requiredAssemblyName];
            }

            AssemblyName assemblyName = new AssemblyName(requiredAssemblyName);
            AssemblyBuilder assemblyBuilder =
                AppDomain.CurrentDomain.DefineDynamicAssembly(
                    assemblyName,
                    AssemblyBuilderAccess.Run);

            ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule(assemblyName.Name);

            moduleBuilderCache[requiredAssemblyName] = moduleBuilder;

            return moduleBuilder;
        }
    }

和 TypeExtentions 类

public static class TypeExtensions
    {
        /// <summary>
        /// extracts all the methods fromthe given interface type and from all the inherited ones too
        /// </summary>
        /// <param name="type">the type fromwhich extracts all the methods</param>
        /// <returns>list of MemberInfo representing the methods</returns>
        public static IEnumerable<MethodInfo> GetAllInterfaceMethods(this Type type)
        {

            IEnumerable<MethodInfo> methods = type.GetMethods();
            foreach (var subType in type.GetInterfaces())
            {
                methods = methods.Union(GetAllInterfaceMethods(subType));
            }
            return methods;
        }
    }

我可以将同步接口转换为异步接口。

如何<{3}}使用预定义的反射异步接口？

var myInterface = new TypeGenerator ( ) . GenerateAsyncInterfaceFor<mySynchronousInterface> ( );

var Client = new DuplexChannelFactory<myInterface> ( new InstanceContext ( new myClass ( ) ) , "myConfiguration" );

我遇到了以下问题：

无法找到类型或命名空间名称'myInterface'（是吗？缺少using指令或程序集引用？）

我正在尝试编写中间层WCF接口。

Answer 1

您使用的语法是编译时键入，当然您正在制作的类型是在运行时生成的，所以它不会起作用。虽然有可能。 How to: Examine and Instantiate Generic Types with Reflection

以下是代码的外观（我假设myClass已经定义了源代码，如果不是，它只是另一个Activator.CreateInstance调用）

Type t = typeof(DuplexChannelFactory<>);
Type typedDuplexChannelFactory = t.MakeGenericType(new Type[]{myInterface});
var Client = Activator.CreateInstance(typedDuplexChannelFactory, new object[]{new InstanceContext ( new myClass ( ) ) , "myConfiguration"});

DuplexChannelFactory＆lt;反射界面＆gt;

1 个答案: