将用java编写的HttpClient转换为C#以调用Web API

我对C#和windows应用程序编程非常陌生

我正在尝试创建一个异步任务，就像在java中一样，在这里我可以查询url并获取其响应

这是我通常在java中使用的代码，我想用C语言实现拷贝

public interface ResponseCallback 
{
    void onSuccess(String response);
    void onFailure(String exception);
}

public class MyAsyncTask extends AsyncTask<String, Void, String> 
{
    private ResponseCallback myResponse = null;
    private int type = 0;//POST
    List<NameValuePair> nameValuePairs = null;
    StringEntity entity = null;

    private HttpResponse response = null;

    public MyAsyncTask(String url,ResponseCallback myResponse)
    {
        this.myResponse = myResponse;
        this.execute(url);
    }


    @Override
    protected String doInBackground(String... param) 
    {
        String url = param[0];

        response = null;
        HttpClient httpclient = new DefaultHttpClient();
        httpclient.getParams().setParameter("http.connection-manager.timeout", 15000);
        try {

            if (type == 0)
            {
                HttpPost httppost = new HttpPost(url);
                if (nameValuePairs != null)
                    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

                if (entity != null)
                    httppost.setEntity(entity);

                response = httpclient.execute(httppost);
            }
            else
            {
                HttpGet httppost = new HttpGet(url);
                response = httpclient.execute(httppost);
            }

        } catch (ClientProtocolException es) 
        {   
        } catch (IOException e) 
        {
        }
        String resp = null;
        if (response != null)
        {
            try {
                  resp = Utilities.convertStreamToString(response.getEntity().getContent());
            } catch (IllegalStateException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return resp;
        }
        else
            return null;
    }

    @Override
    protected void onPostExecute(String resp) 
    {
        if (resp != null)
        {          
            if (response.getStatusLine().getStatusCode() == Constants.RESULT_OK )
            {
                try {
                      myResponse.onSuccess(resp.trim());
                } catch (IllegalStateException e) {
                }
            }
            else
                 myResponse.onFailure(resp);
        }
        else
            myResponse.onFailure(resp);
    }
}   

---

您的

回调

字段是一个实例字段，因此您不能从静态方法访问它，除非您将该字段设置为静态

不过，我想推荐的另一种选择是根本不使用字段。将回调变量作为方法参数传递

---

或者你可以完全停止使用静态方法，让它们成为实例方法。

我不完全确定它是否能满足你的所有需要，但我会考虑使用该类中可用的

…Async

函数来异步下载。@MichaelTodd有几点，我想检查，首先我不能调用callback.onSuccess（jsonStr）；为什么我不能使用这个变量？第二，获取响应字符串的正确方法您是否设置了回调函数？Where？@MichaelTodd我在MyAsyncTask中定义了一个接口和一个变量，请检查我如何在Java中使用接口如果“回调变量未被识别”，则错误在于设置回调变量。我会首先考虑解决这个问题，然后担心您的HttpClient转换是否成功。

namespace The_Vow.Global
{
    class MyAsyncTask
    {
        public ResponseCallback callback;

        static void queryUrl(String url)
        {
            RunAsync(url).Wait();
        }

        static async Task RunAsync(String url)
        {
            using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri("MY_IP");
                client.DefaultRequestHeaders.Accept.Clear();
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                // HTTP GET
                HttpResponseMessage response = await client.GetAsync(url);
                //response = await client.PostAsJsonAsync("api/products", gizmo);

                if (response.IsSuccessStatusCode)
                {
                    String jsonStr = await response.Content.ReadAsStringAsync();

// callback variable is not being recognized????
callback.onSuccess(jsonStr);

                    //Console.WriteLine("{0}\t${1}\t{2}", product.Name, product.Price, product.Category);
                }
            }
        }

    }
}


    namespace The_Vow.Global
    {
            public interface ResponseCallback
            {
                void onSuccess(String response);
                void onFailure(String exception);
            }
    }