在 MonoTouch 中注册自定义 NSUrlProtocol

我正在使用MonoTouch构建一个iOS应用程序，并尝试实现自定义NSUrlProtocol。

当我注册自己的协议实现时，出现以下错误：

WebKit 丢弃了 webView：decisionidePolicyForNavigationAction：request：frame：decisionListener： 委托： * -canInitWithRequest： 仅 为抽象类定义。 定义 -[Foo.Network.NetworkServices+TestProtocol canInitWithRequest：]！

关于可能导致这种情况的原因的任何想法？

这是代码：

//Registering the protocol    
NSUrlProtocol.RegisterClass(new Class(typeof(TestProtocol)));
public class TestProtocol : NSUrlProtocol
{
    public TestProtocol ()
    {
        this.Client = new TestProtocolClient(); 
    }       
    public override bool CanInitWithRequest (NSUrlRequest request)
    {
        return true;
    }
}
public class TestProtocolClient : NSUrlProtocolClient
{
    public override void DataLoaded (NSUrlProtocol protocol, NSData data)
    {
    }
    public override void FailedWithError (NSUrlProtocol protocol, NSError error)
    {
    }
    public override void ReceivedResponse (NSUrlProtocol protocol, NSUrlResponse response, NSUrlCacheStoragePolicy policy)
    {
    }
    public override void Redirected (NSUrlProtocol protocol, NSUrlRequest redirectedToEequest, NSUrlResponse redirectResponse)
    {
    }
    public override void CachedResponseIsValid (NSUrlProtocol protocol, NSCachedUrlResponse cachedResponse)
    {
    }
    public override void FinishedLoading (NSUrlProtocol protocol)
    {
    }
    public override void ReceivedAuthenticationChallenge (NSUrlProtocol protocol, NSUrlAuthenticationChallenge challenge)
    {
    }
    public override void CancelledAuthenticationChallenge (NSUrlProtocol protocol, NSUrlAuthenticationChallenge challenge)
    {
    }
}