C# HttpClient 用法

Question

我正在尝试使用 HttpClient 和异步编写以下代码，但它无法返回数据。

        WebRequest request = WebRequest.Create("some_url");
        request.Headers.Add("cookie", "some_cookie");

        Stream objStream = request.GetResponse().GetResponseStream();
        StreamReader objReader = new StreamReader(objStream);
        string sLine = "";
        int i = 0;
        while (sLine != null)
        {
            i++;
            sLine = objReader.ReadLine();
            if (sLine != null)
                Console.WriteLine(sLine);
        }

这是我尝试过的。

        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Add("cookie", "some_cookie");
            using (var response = await client.GetAsync("some_url"))
            {
                string responseData = await response.Content.ReadAsStringAsync();
                Console.WriteLine(responseData);
            }
        }

任何帮助将不胜感激。

编辑：这是使用 HttpClient 对我有用的代码。

        var baseAddress = new Uri(baseUrl);
        using (var handler = new HttpClientHandler { UseCookies = false })
        using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
        {
            var requestMessage = new HttpRequestMessage(HttpMethod.Get, queryString);
            requestMessage.Headers.Add("cookie", cookie);
            var response = client.SendAsync(requestMessage);
            response.Wait();
            var content = response.Result.Content.ReadAsStringAsync();
            content.Wait();
            Console.WriteLine(content.Result);
        }

感谢所有的帮助。

Answer 1

您正在执行异步和等待，但您不是在等待返回或到达响应数据，因此以下代码段将完成这项工作：

试试这个代码：

  static async Task<string> HttpGetResponse()
    {
        WebRequest request = WebRequest.Create("some_url");
        request.Headers.Add("cookie", "some_cookie");
        string responseData;
        Stream objStream = request.GetResponse().GetResponseStream();
        StreamReader objReader = new StreamReader(objStream);
        string sLine = "";
        int i = 0;
        while (sLine != null)
        {
            i++;
            sLine = objReader.ReadLine();
            if (sLine != null)
                Console.WriteLine(sLine);
        }

        using (var client = new HttpClient())
        {
            client.DefaultRequestHeaders.Add("cookie", "some_cookie");
            using (var response = await client.GetAsync("some_url"))
            {
                responseData = await response.Content.ReadAsStringAsync();
                Console.WriteLine(responseData);
            }
        }

        return responseData;
    }

在主要调用它是这样的：

static void Main(string[] args)
   {
       Task<string> t = HttpGetResponse();


      //Do alot of work

       t.Wait();
       string response = t.Result;

       Console.WriteLine(response);
   }

希望这是有用的。