如何处理IParameterInspector中引发的异常

Question

我到处找都找不到答案。我有一个使用IParameterInspector的扩展端点行为。当异常在BeforeCall方法中抛出时，我如何处理它？

我已经尝试将try-catch添加到IEndPointBehavior和BehaviorExtensionElement中，这两个元素都不能处理它

BehaviorExtensionElement：

public class ExtensionService : BehaviorExtensionElement
{
    protected override object CreateBehavior()
    {
        //try-catch doesn't work here
        return new ExtensionBehavior();
    }
    public override Type BehaviorType
    {
        get { return typeof(ExtensionBehavior); }
    }
}

IEndpointBehavior:

public class ExtensionBehavior : IEndpointBehavior
{
    public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
    {
        //throw new NotImplementedException();
    }
    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        foreach (ClientOperation clientOperation in clientRuntime.ClientOperations)
        {
            //try-catch here doesn't work
            clientOperation.ClientParameterInspectors.Add(new ParamInspector());
        }
    }
    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        foreach (DispatchOperation dispatchOperation in endpointDispatcher.DispatchRuntime.Operations)
        {
                //try-catch here doesn't work
                dispatchOperation.ParameterInspectors.Add(new ParamInspector());
        }
    }
    public void Validate(ServiceEndpoint endpoint)
    {
        //throw new NotImplementedException();
    }
}

IParameterInspector

public class ParamInspector : IParameterInspector
{
    public void AfterCall(string operationName, object[] outputs, object returnValue, object correlationState)
    {
    }
    public object BeforeCall(string operationName, object[] inputs)
    {
        ///an exception is thrown here
        return null;
    }
}

Answer 1

我终于解决了这个问题。我不得不像这样实现IErrorHandler：

public class CustomErrorHandler : IErrorHandler
{
    public bool HandleError(Exception error)
    {
        //the procedure for handling the errors.
        //False is returned because every time we have an exception we want to abort the session.
        return false;
    }
    public void ProvideFault(Exception error, System.ServiceModel.Channels.MessageVersion version, ref System.ServiceModel.Channels.Message fault)
    {
    }
}

然后将此IErrorHandler添加到ApplyDispatchBehavior

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        foreach (DispatchOperation dispatchOperation in endpointDispatcher.DispatchRuntime.Operations)
        { 
                dispatchOperation.ParameterInspectors.Add(new ParamInspector(this.Class));
        }
        endpointDispatcher.ChannelDispatcher.ErrorHandlers.Add(new CustomErrorHandler());
    }