根据我的问题(通用方法的可重用非通用方法),我已经实现了提供的解决方案,但是经过一些重构(将代码移动到基类),我的代码导致了我不理解的 StackOverflowException。
对Handle(new TestCommand())
结果的调用IMessageHandler.Handle(IMessage)
被调用,然后Handle<TMessage>(TMessage)
被调用,但不是调用Handle(TestCommand message)
继承的类,而是IMessageHandler.Handle(IMessage)
再次调用。
泛型方法中的 as-cast toIMessageHandler<TestCommand>
有效,否则它将调用HandleUnknownMessage(IMessage)
.
很难描述,所以这里是我的测试代码:
class Program {
static void Main(string[] args) {
MyProcess p = new MyProcess();
IMessageHandler handler = p;
handler.Handle(new DummyCommand()); // works -> HandleUnknownMessage gets called as expected
handler.Handle(new TestCommand()); // fails -> results in a StackOverflowException
}
}
public abstract class ProcessBase : IMessageHandler {
void IMessageHandler.Handle(IMessage message) {
System.Diagnostics.Debug.WriteLine("Dynamic Message gets handled");
dynamic dynamicMessage = message;
Handle(dynamicMessage);
}
private void Handle<TMessage>(TMessage message) where TMessage : IMessage {
System.Diagnostics.Debug.WriteLine("Generic Message gets handled");
var handler = this as IMessageHandler<TMessage>;
if (handler == null)
HandleUnknownMessage(message);
else
handler.Handle(message);
}
protected virtual void HandleUnknownMessage(IMessage unknownMessage) {
System.Diagnostics.Debug.WriteLine("Unknown message {0} passed to Process".FormatWith(unknownMessage.GetType()));
// Handle unknown message types here.
}
}
public class MyProcess : ProcessBase, IMessageHandler<TestCommand>, IMessageHandler<TestEvent> {
public void Handle(TestCommand commandMessage) {
System.Diagnostics.Debug.WriteLine("TestCommand gets handled");
}
public void Handle(TestEvent eventMessage) {
System.Diagnostics.Debug.WriteLine("TestEvent gets handled");
}
}
public class DummyCommand : IMessage { }
public class TestCommand : IMessage { }
如果我将代码从我的基类ProcessBase
放到MyProcess
,代码可以正常工作。将动态关键字与泛型方法和继承结合使用是否有任何限制?