写在前面

在上一篇中对AspectCore进行了初步的了解，用于拦截的属性加在了具体类的方法上。

C# 面向切面编程之AspectCore初探

这一篇验证一下把拦截属性加在接口上，这样实现该接口的类中所对应的方法都会被拦截到；另外示例中还尝试对方法的入参进行了修改，验证了通过AspectContext可以获得当前方法的所有信息。

代码实现

using AspectCore.DynamicProxy;
using AspectCore.DynamicProxy.Parameters;

class Program
{
    static void Main(string[] args)
    {
        ProxyGeneratorBuilder proxyGeneratorBuilder = new ProxyGeneratorBuilder();
        IProxyGenerator proxyGenerator = proxyGeneratorBuilder.Build();
        SampleInterface sampleInterface = proxyGenerator.CreateInterfaceProxy<SampleInterface, SampleClass>();
        Console.WriteLine(sampleInterface);
        var ret = sampleInterface.Foo(1);
        Console.WriteLine("ret:" + ret);
        sampleInterface.Boo();

        Console.ReadKey();
    }
}

public class SampleInterceptor : AbstractInterceptorAttribute
{
    public override Task Invoke(AspectContext context, AspectDelegate next)
    {
        try
        {
            Console.WriteLine("Call Interceptor Start");
            if (context.ImplementationMethod.Name.Equals("Foo"))
            {
                if (context.Parameters.Length > 0)
                {
                    Console.WriteLine($"Foo Parameter Value[0]:{context.Parameters[0]}");
                    context.Parameters[0] = 2;
                }
                var returnParam = context.GetReturnParameter();
                if (returnParam != null)
                {
                    Console.WriteLine($"return type: {returnParam.Type.Name}");
                }                
            }
            return context.Invoke(next);
        }
        catch (Exception ex)
        {
            throw;
        }
        finally
        {
            Console.WriteLine("Call Interceptor End");
        }
    }
}

public class SampleClass : SampleInterface
{
    public virtual int Foo(int a)
    {
        Console.WriteLine("Call Foo:" + a);
        return 1;
    }

    public virtual void Boo()
    {
        Console.WriteLine("Call Boo");
    }
     
}

[SampleInterceptor]
public interface SampleInterface
{
    int Foo(int a);

    void Boo();
}

调用示例