在 C# 中从 API 获取数据

Question

我正在尝试使用 C# 从开放 API 获取数据。

在下面的代码中，我设法创建了一个 HttpClient 对象，但我无法获得 http 响应。我有一些Console.Writeline() 来帮助我定位错误，我打印的最后一件事是

创建的 HTTP 客户端

所以我似乎没有得到回应。谁能告诉我怎么回事？

using System;
using System.Net.Http;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;

namespace CodeTesting
{
    public class Parser
    {
        public Parser()
        {
            Console.WriteLine("Created parser");
            GetQuestion();
        }

        public static async void GetQuestion()
        {
            Console.WriteLine("INSIDE GETQUESTION");
            string baseUrl = "https://opentdb.com/api.php?amount=10&category=15&difficulty=easy";

            try
            {
                using (HttpClient client = new HttpClient())
                {
                    Console.WriteLine("Created HTTPClient");

                    using (HttpResponseMessage res = await client.GetAsync(baseUrl))
                    {
                        Console.WriteLine("GOT HTTP RESPONSE");

                        using (HttpContent content = res.Content)
                        {
                            Console.WriteLine("RETRIEVING CONTENT");
                            var data = await content.ReadAsStringAsync();
                            if (data != null)
                            {
                                Console.WriteLine("data------------{0}", data);
                            }
                            else
                            {
                                Console.WriteLine("NO Data----------");
                            }
                        }
                    }
                }
            }
            catch (Exception exception)
            {
                Console.WriteLine("Exception Hit------------");
                Console.WriteLine(exception);
            }
        }
    }
}

Answer 1

只需从 HttpResponseMessage 中删除 await 并在 GetAsync() 函数的末尾添加“.Result”，下面的代码就可以工作了。

using System;
using System.Net.Http;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;

namespace CodeTesting
{
    public class Parser
    {
        public Parser()
        {
            Console.WriteLine("Created parser");
            GetQuestion();
        }
        public static async void GetQuestion()
        {
            Console.WriteLine("INSIDE GETQUESTION");
            string baseUrl = "https://opentdb.com/api.php?amount=10&category=15&difficulty=easy";

            try
            {

                using (HttpClient client = new HttpClient())
                {
                    Console.WriteLine("Created HTTPClient");

                    using (HttpResponseMessage res = client.GetAsync(baseUrl).Result)
                    {
                        Console.WriteLine("GOT HTTP RESPONSE");

                        using (HttpContent content = res.Content)
                        {
                            Console.WriteLine("RETRIEVING CONTENT");

                            var data = await content.ReadAsStringAsync();

                            if (data != null)
                            { Console.WriteLine("data------------{0}", data);}
                            else
                            { Console.WriteLine("NO Data----------"); }
                        }
                    }
                }
            }
            catch (Exception exception)
            {
                Console.WriteLine("Exception Hit------------");
                Console.WriteLine(exception);
            }
        }
    }
}

Answer 2

只需等待 http 客户端获取值。 所以你的解析器会是这样的，

public Parser()
        {
            Console.WriteLine("Created parser");
            GetQuestion();
            Console.ReadLine();
        }

注意：这不是解决方案，但要解除阻止，请尝试此操作以便查看输出。

输出：

创建的解析器
内部问题
创建 HTTPClient
得到 HTTP 响应
检索内容
data------------{"response_code":0,"results":[{"category":"Entertainment: Video Games","type":"multiple","difficulty":" easy","question":"被取消的军团要塞续集叫什么名字？","correct_answer":"军团要塞 2：兄弟会","incorrect_answers":["军团要塞 2：沙漠雇佣兵", "军团要塞 2：磨牙机行动","军团要塞 2：回归经典"]},{"category":"娱乐：电子游戏","type":"boolean","difficulty":"easy", “问题”：“在“超级马里奥 64”中，在一个关卡中收集 100 个硬币会给你一个 1-UP。”，“正确答案”：“错误”，“错误答案”：[“真”]}，{“类别":"Entertainment: Video Games","type":"boolean","difficulty":"easy","question":"Niko Bellic 是 Grand Theft Auto IV 的主角。","correct_answer":"True" ,"incorrect_answers":["False"]},{"category":"娱乐：电子游戏","type":"multiple","difficulty":"easy","question":"游戏是哪一年“守望先锋”进入封闭测试版？","correct_answer":"2015","incorrect_ans wers":["2013","2011","2016"]},{"category":"娱乐：电子游戏","type":"multiple","difficulty":"easy","question": "有多少不同形状的俄罗斯方块？","correct_answer":"7","incorrect_answers":["5","6","8"]},{"category":"娱乐：视频游戏" ,"type":"multiple","difficulty":"easy","question":"哪款电子游戏因其隐藏的“热咖啡”小游戏而引发争议？","correct_answer":"侠盗猎车手：圣安地列斯","incorrect_answers":["Grand Theft Auto: Vice City","Hitman: Blood Money","Cooking Mama"]},{"category":"Entertainment: Video Games","type":"multiple", "difficulty":"easy","question":"银河战士系列的名字来源于什么？","correct_answer":"游戏中的敌人","incorrect_answers":["最终boss的名字","主角的名字","宇宙飞船的名字"]},{"category":"娱乐：电子游戏","type":"multiple","difficulty":"easy","question":"哪个以下不是游戏《王国之心：S》中的可玩角色leep?","correct_answer":"Ignis","incorrect_answers":["Ventus","Terra","Aqua"]},{"category":"娱乐：电子游戏","type":"multiple" ,"difficulty":"easy","question":"谁是真人快打世界末日之战的真正胜利者？","correct_answer":"Shao Kahn","incorrect_answers":["刘康","尚宗","雷电"]},{"category":"娱乐：电子游戏","type":"multiple","difficulty":"easy","question":"In "Mario & Sonic at the Olympic Games》，角色分为几种类型？","correct_answer":"4","incorrect_answers":["6","5","3"]}]}