.NET의 생성자없이 클래스를 상속하는 방법이 있습니까?

Question

현재 일부 HTTPWebRequest 함수를 수정하려고 노력하고 있지만 HTTPWebRequest에는 공개 생성자가 없기 때문에 상속을 통해 수행 할 수 없습니다 (사막화 생성자 외에). 이 작업을 수행하는 해결 방법이 있습니까?

내 목표는 아래 예제와 같은 것을 코딩하는 것이지만,이 클래스 객체는 httpwebrequest 속성 및 방법을 상속해야합니다.

using System;
using System.Net;
using System.Threading;

public class AsyncWebRequest:WebRequest
{
    private readonly AsyncCallback getResponseCallback;
    private readonly Uri uri;
    private volatile int RetriesLeft = 3;
    private volatile WebRequest request;

    public AsyncWebRequest(string uri, AsyncCallback getResponseCallback)
       :this(new Uri(uri), getResponseCallback)
    {
    }

    public AsyncWebRequest(Uri uri, AsyncCallback getResponseCallback):base()
    {
        this.uri = uri;
        this.getResponseCallback = getResponseCallback;
    }

    private IAsyncResult BeginGetResponse()
    {
        request = HttpWebRequest.CreateDefault(uri);
        ((HttpWebRequest)request).ReadWriteTimeout = Timeout;
        var result = request.BeginGetResponse(GetResponseCallback, null);
        ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle,
            GetResponseTimeout, null, Timeout, true);
        return result;
    }

    private void GetResponseTimeout(object state, bool timedOut)
    {
        if (timedOut)
        {
            Retry();
        }
    }

    private void Retry()
    {
        request.Abort();
        bool retry = false;
        lock (request)
        {
            if (RetriesLeft > 0)
            {
                Interlocked.Decrement(ref RetriesLeft);
                retry = true;
            }
        }
        if (retry)
        {
            BeginGetResponse();
        }
        else
        {
            getResponseCallback(null);
        }
    }

    private void GetResponseCallback(IAsyncResult AsyncResult)
    {
        try
        {
            getResponseCallback(AsyncResult);
        }
        catch(WebException webException)
        {
            Retry();
        }
    }
}

Answer 1

직렬화 생성자를 속일 수 없다면 입찰을 수행 할 수 없습니다. 그렇지 않으면 방법이 없습니다.

해당 클래스의 생성자는 내부이므로 전화 할 방법이 없습니다.

Answer 2

You can't through inheritance from HttpWebRequest (if you don't want to call the serialization constructor) , but you can through composition and delegation, and through inheritance from WebRequest (I'm not sure if that will do it for you, but functionally it is quite similar). WebRequest has a default constructor.

In this case you then can't have the class 'be' a HttpWebRequest (as in an is-a relationship), since you can't extend from it, but it wil 'be' a WebRequest, which should suffice.

You could write a class that inherits from WebRequest, that has an instance member of type WebRequest, create a HttpWebRequest and assign to instance member in the constructor of the new type and delegate all calls to that reference (sort of a decorator pattern):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;

namespace ClassLibrary1
{
    public class MyHttpWebRequest : WebRequest
    {
        private WebRequest request;

        public MyHttpWebRequest(string uri)
        {
            request = HttpWebRequest.Create(uri);
        }

        public override WebResponse GetResponse()
        {
            // do your extras, or just delegate to get the original code, as long
            // as you still keep to expected behavior etc.
            return request.GetResponse();
        }

    }
}