所以根据 Remus 的回答，这是我的解决方法

So based on Remus's answer this is my workaround

        public Message SendData(Message requestMessage)
    {
        var channel = CreateChannel();
        Message responseMessage;
        using (new OperationContextScope((IClientChannel)channel))
        {
            WebOperationContext.Current.OutgoingRequest
                .Headers[HttpRequestHeader.Authorization] = "Basic "
                + Convert.ToBase64String(Encoding.ASCII.GetBytes(
                Credentials.UserName.UserName + ":" + Credentials.UserName.Password));
            responseMessage = channel.SendData(requestMessage); 
        }
        return responseMessage;
    }

我只是强迫第一个请求使用基本授权

I'm simply forcing first request to go out with Basic Authorization