4
我想應用一些使用本地生長類型的「aspect」的行爲，真的是.net屬性。我有一個基礎類（BankingServiceBase），它在啓動時反映自己，看看應用了哪些「方面」。然後它可以在操作之前或之後執行自定義行爲。我使用Autofac作爲我的IOC容器。我正在嘗試將PropertiesAutowired方法應用於方面的註冊。在下面的示例代碼中，我希望Autofac爲我的aspect/attribute注入一個ILog實例。然而，它並沒有這樣做。我的猜測是，當我撥打GetCustomAttributes時，它會創建一個新實例，而不是從Autofac獲取已註冊的實例。思考？下面是一些可用的示例代碼顯示的問題：如何在.net屬性中注入屬性依賴關係？
internal class Program
{
private static void Main()
{
var builder = new ContainerBuilder();
builder
.RegisterType<ConsoleLog>()
.As<ILog>();
builder
.RegisterType<BankingService>()
.As<IBankingService>();
builder
.RegisterType<LogTransfer>()
.As<LogTransfer>()
.PropertiesAutowired();
var container = builder.Build();
var bankingService = container.Resolve<IBankingService>();
bankingService.Transfer("ACT 1", "ACT 2", 180);
System.Console.ReadKey();
}
public interface IBankingService
{
void Transfer(string from, string to, decimal amount);
}
public interface ILog
{
void LogMessage(string message);
}
public class ConsoleLog : ILog
{
public void LogMessage(string message)
{
System.Console.WriteLine(message);
}
}
[AttributeUsage(AttributeTargets.Class)]
public abstract class BankingServiceAspect : Attribute
{
public virtual void PreTransfer(string from, string to, decimal amount)
{
}
public virtual void PostTransfer(bool success)
{
}
}
public class LogTransfer : BankingServiceAspect
{
// Note: this is never getting set from Autofac!
public ILog Log { get; set; }
public override void PreTransfer(string from, string to, decimal amount)
{
Log.LogMessage(string.Format("About to transfer from {0}, to {1}, for amount {2}", from, to, amount));
}
public override void PostTransfer(bool success)
{
Log.LogMessage(success ? "Transfer completed!" : "Transfer failed!");
}
}
public abstract class BankingServiceBase : IBankingService
{
private readonly List<BankingServiceAspect> aspects;
protected BankingServiceBase()
{
// Note: My guess is that this "GetCustomAttributes" is happening before the IOC dependency map is built.
aspects =
GetType().GetCustomAttributes(typeof (BankingServiceAspect), true).Cast<BankingServiceAspect>().
ToList();
}
void IBankingService.Transfer(string from, string to, decimal amount)
{
aspects.ForEach(a => a.PreTransfer(from, to, amount));
try
{
Transfer(from, to, amount);
aspects.ForEach(a => a.PostTransfer(true));
}
catch (Exception)
{
aspects.ForEach(a => a.PostTransfer(false));
}
}
public abstract void Transfer(string from, string to, decimal amount);
}
[LogTransfer]
public class BankingService : BankingServiceBase
{
public override void Transfer(string from, string to, decimal amount)
{
// Simulate some latency..
Thread.Sleep(1000);
}
}
}
-1爲什麼在世界上，你會想要寫一個類反思自己？有幾個容器通過截取框來支持AOP。就[快速谷歌搜索顯示]（http://code.google.com/p/autofac/wiki/DynamicProxy2）Autofac也支持這一點。 – 2012-02-22 10:03:42