namespace CustomAttribute
{public interface ILog{void log(string msg);}
}

[Serializable]public class Logger:ILog{public void log(string msg){string path = Environment.CurrentDirectory + "\\" + string.Format("systemlog/{0}/{1}/{2}", "error", DateTime.Now.Year, DateTime.Now.Month);if (!Directory.Exists(path)){Directory.CreateDirectory(path);}string logPath = path + "/" + DateTime.Today.ToString("yyyy-MM-dd") + ".txt";if (!File.Exists(logPath)){var file = File.Create(logPath);file.Close();}StreamWriter sw = new StreamWriter(logPath, true);sw.WriteLine(msg);sw.Flush();sw.Close();}}

[Serializable][AttributeUsage(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]public class ExceptionLogAttribute : OnMethodBoundaryAspect{private ILog logger;//通过依赖注入的方式解耦public ExceptionLogAttribute(ILog log){logger = log;}public override void OnException(MethodExecutionArgs args){base.OnException(args);logger.log(string.Format("{0}:{1}", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), args.Exception.Message));}}

[Serializable][AttributeUsage(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]//AttributeTargets.Method说明该特性是应用到方法上的

public sealed class MyExceptionLogAttribute:ExceptionLogAttribute { public MyExceptionLogAttribute() : base(new Logger()) { } }

class Program{static void Main(string[] args){Console.WriteLine(Divide(1, 0));Console.ReadLine();}[MyExceptionLog]private static int Divide(int a, int b){return a / b;}}