重量级的ORM和IOC产品离不开动态代理，作为开发人员，多数情况不用关注动态代理的内部实现机制，但是了解其一般的规律和模式还是有必要的，比如：虽然你开发期间采用了POCO，因为开启了动态代理，运行期间则不是POCO。本文简单描述了5种代理生成模式和1种Mixin模式，最后给出一个示例。

复制代码 代码如下:
public interface IPlayable
{
void Play();
}

public class Animal : IPlayable
{
public virtual void Play()
{
Console.WriteLine("Animal.Play");
}
}

public class Dog : Animal
{
public override void Play()
{
Console.WriteLine("Dog.Play");
}
}

public interface IRunable
{
void Run();
}

public class RunAbility : IRunable
{
public void Run()
{
Console.WriteLine("RunAbility.Run");
}
}

public class AnimalInterceptor : IInterceptor
{
public void Intercept(IInvocation invocation)
{
Console.WriteLine("Before AnimalInterceptor.Intercept");
if (invocation.InvocationTarget != null)
{
invocation.Proceed();
}
Console.WriteLine("After AnimalInterceptor.Intercept");
}
}

第一种：ClassProxy

复制代码 代码如下:
{
Console.WriteLine("\n*************ClassProxy*************\n");
var generator = new ProxyGenerator();
var animal = generator.CreateClassProxy<Animal>(new AnimalInterceptor());
animal.Play();

Console.WriteLine(animal.GetType());
Console.WriteLine(animal.GetType().BaseType);

var compositeField = animal.GetType().GetField("__target");
Console.WriteLine(compositeField);

foreach (var interfaceType in animal.GetType().GetInterfaces())
{
Console.WriteLine(interfaceType);
}
}

第二种：ClassProxyWithTarget

复制代码 代码如下:
{
Console.WriteLine("\n*************ClassProxyWithTarget*************\n");
var generator = new ProxyGenerator();
var animal = generator.CreateClassProxyWithTarget<Animal>(new Dog(), new AnimalInterceptor());
animal.Play();

Console.WriteLine(animal.GetType());
Console.WriteLine(animal.GetType().BaseType);

var compositeField = animal.GetType().GetField("__target");
Console.WriteLine(compositeField);

foreach (var interfaceType in animal.GetType().GetInterfaces())
{
Console.WriteLine(interfaceType);
}
}

第三种：InterfaceProxyWithoutTarget

复制代码 代码如下:
{
Console.WriteLine("\n*************InterfaceProxyWithoutTarget*************\n");
var generator = new ProxyGenerator();
var animal = generator.CreateInterfaceProxyWithoutTarget<IPlayable>(new AnimalInterceptor());
animal.Play();

Console.WriteLine(animal.GetType());
Console.WriteLine(animal.GetType().BaseType);

var compositeField = animal.GetType().GetField("__target");
Console.WriteLine(compositeField);

foreach (var interfaceType in animal.GetType().GetInterfaces())
{
Console.WriteLine(interfaceType);
}
}

第四种：InterfaceProxyWithTarget

复制代码 代码如下:
{
Console.WriteLine("\n*************InterfaceProxyWithTarget*************\n");
var generator = new ProxyGenerator();
var animal = generator.CreateInterfaceProxyWithTarget<IPlayable>(new Dog(), new AnimalInterceptor());
animal.Play();

Console.WriteLine(animal.GetType());
Console.WriteLine(animal.GetType().BaseType);

var compositeField = animal.GetType().GetField("__target");
Console.WriteLine(compositeField);

foreach (var interfaceType in animal.GetType().GetInterfaces())
{
Console.WriteLine(interfaceType);
}
}

第五种：InterfaceProxyWithTargetInterface

复制代码 代码如下:
{
Console.WriteLine("\n*************InterfaceProxyWithTargetInterface*************\n");
var generator = new ProxyGenerator();
var animal = generator.CreateInterfaceProxyWithTargetInterface<IPlayable>(new Dog(), new AnimalInterceptor());
animal.Play();

Console.WriteLine(animal.GetType());
Console.WriteLine(animal.GetType().BaseType);

var compositeField = animal.GetType().GetField("__target");
Console.WriteLine(compositeField);

foreach (var interfaceType in animal.GetType().GetInterfaces())
{
Console.WriteLine(interfaceType);
}
}

Mixin模式

复制代码 代码如下:
{
Console.WriteLine("\n*************Mixin*************\n");
var generator = new ProxyGenerator();
var options = new ProxyGenerationOptions();
options.AddMixinInstance(new RunAbility());
var animal = generator.CreateClassProxy<Animal>(options, new AnimalInterceptor());
animal.Play();
(animal as IRunable).Run();

Console.WriteLine(animal.GetType());
Console.WriteLine(animal.GetType().BaseType);

var compositeField = animal.GetType().GetField("__target");
Console.WriteLine(compositeField);

foreach (var field in animal.GetType().GetFields())
{
if (field.Name.StartsWith("__mixin"))
{
Console.WriteLine(field);
}
}

foreach (var interfaceType in animal.GetType().GetInterfaces())
{
Console.WriteLine(interfaceType);
}
}