MonoTouch WCF REST 创建通道时出错

Question

我正在尝试通过 MonoTouch 访问 WCF REST 服务。我无法使用 ChannelFactory，因为在 MonoTouch 中无法生成动态代码，并且因为我正在访问 RESTful 服务，所以我也无法使用 svcutil 来构建客户端类。

这让我不得不手动构建客户端类。我已经走了很远，但遇到了问题，这是我的代理类代码：

public class AuthenticationClient : System.ServiceModel.ClientBase<IAuthenticationService>, IAuthenticationService
{
    public AuthenticationClient(Binding binding, EndpointAddress baseAddress) : base(binding, baseAddress)
    { } 

    public AuthenticationResult AuthenticateUser (AccountCredentials credentials)
    {
        return base.Channel.AuthenticateUser(credentials);
    }

    protected override IAuthenticationService CreateChannel ()
    {
        // This method must be overriden in MonoTouch to prevent using a ChannelFactory
        return new AuthenticationChannel(this);
    }

    private class AuthenticationChannel : ChannelBase<IAuthenticationService>, IAuthenticationService
    {
         public AuthenticationChannel(System.ServiceModel.ClientBase<IAuthenticationService> client) : 
            base(client)
        { }

        public AuthenticationResult AuthenticateUser (AccountCredentials credentials)
        {
            object[] _args = new object[1];
            _args[0] = credentials;

            return (AuthenticationResult)base.Invoke("AuthenticateUser", _args); // Exception thrown here       
        }
    }   
}

接口 IAuthenticationService 使用属性来指定端点 Uri：

[ServiceContract]
public interface IAuthenticationService
{
    [OperationContract]
    [WebInvoke(Method = "POST", UriTemplate = "/Authenticate/User")]
    AuthenticationResult AuthenticateUser(AccountCredentials credentials);
}

这是我使用代理类的方式：（

var serviceHost = "http://mydomain.com/";
var servicePath = "Services/Authentication";

Uri hostUri = new Uri(serviceHost);
Uri serviceUri = new Uri(hostUri, servicePath);

var binding = new WebHttpBinding();

var client = new AuthenticationClient(binding, new EndpointAddress(serviceUri));

client.Endpoint.Behaviors.Add(new MyWebHttpBehaviour());

var credentials = new AccountCredentials
{
    Username = "myusername",
    Password = "mypassword"
};

var result = client.AuthenticateUser(credentials);      

出于某种原因，WebHttpBehavior 不实现 IEndpointBehavior，因此我创建了自己的类，该类继承自 WebHttpBehavior 并且也实现了 IEndpointBehavior）。

我收到的异常是：

System.InvalidOperationException：在传输上启用手动寻址时，每个请求消息都必须设置其目标地址。

有人可以帮忙吗？

干杯， 安东尼.