[英]request.GetResponse() seems to hang up my program
我一直在研究通過httprequests從其他服務器獲取結果的項目。 在這種情況下,我嘗試並成功(昨天,相同的代碼也起作用。)搜索國家/地區並將其標志設置為dipslay。
我已經縮小了函數“ makeRequest”的范圍。
通過掛斷,我的意思是我什至不能通過單擊右上角的“ x”來關閉表單,而必須通過單擊“停止調試”來強制退出。
任何提示,我在做什么錯了或出錯了,將不勝感激。
表單使用的代碼:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
namespace ApiQueryHandler
{
abstract class QueryCreator
{
static public string createQueryLandcode(String country)
{
string queryStandaard = "https://restcountries.eu/rest/v2/name/";
string queryLandCode = "?fields=alpha2Code";
string query = queryStandaard + country + queryLandCode;
return query;
}
static public string makeRequest(string query)
{
WebRequest request = WebRequest.Create(query);
request.Credentials = CredentialCache.DefaultCredentials;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
reader.Close();
dataStream.Close();
response.Close();
return responseFromServer;
}
static public string createQueryFlag(string country)
{
string queryStandaard = "https://restcountries.eu/rest/v2/name/";
string queryFlag = "?fields=flag";
string query = queryStandaard + country + queryFlag;
return query;
}
static public string getSVGFlagUrl(string queryResponseFlag)
{
String beginUrl = queryResponseFlag.Substring(10);
int endUrl = beginUrl.IndexOf('"');
String url = queryResponseFlag.Substring(10,endUrl);
return url;
}
static public string getPNGFlagUrl(string landCode)
{
string PNGUrl = "https://www.countryflags.io/"+landCode+"/flat/64.png";
return PNGUrl;
}
static public string getCode(string queryResponseCode)
{
String beginCode = queryResponseCode.Substring(16);
int endCode = beginCode.IndexOf('"');
String code = queryResponseCode.Substring(16, endCode);
return code;
}
static public string getCodeShort(string queryResponseCode)
{
String beginCode = queryResponseCode.Substring(10);
int endCode = beginCode.IndexOf('"');
String code = queryResponseCode.Substring(10, endCode-1);
return code;
}
}
}
表單代碼:
private void textBoxCounrty_TextChanged(object sender, EventArgs e)
{
string country = textBoxCountry.Text;
string queryLandcode = QueryCreator.createQueryLandcode(country);
string queryFlag = QueryCreator.createQueryFlag(country);
try
{
string responseLandcode = QueryCreator.makeRequest(queryLandcode);
string responseFlag = QueryCreator.makeRequest(queryFlag);
string SVGUrl = QueryCreator.getSVGFlagUrl(responseFlag);
labelURLQuery.Text = queryLandcode;
string processedLandcode = QueryCreator.getCode(responseLandcode);
string PNGUrl = QueryCreator.getPNGFlagUrl(processedLandcode);
richTextBoxServerResponse.Text = responseLandcode+"\n\n"+processedLandcode+"\n\n"+PNGUrl+"\n\n"+SVGUrl;
pictureBoxFlag.Load(PNGUrl);
labelERROR.Text = "";
}
catch (WebException)
{
labelERROR.Text = "404 not found";
}
catch (ArgumentException)
{
labelERROR.Text = "404 not found";
}
}
使您的請求異步
public async Task<string> makerequest(string query){
}
然后在調用它時使用await修飾符
string response= await makerequest(yourstring)
異步執行此操作可以停止掛起的問題。 重要的是要注意,您不必使調用方法與之異步,因為只能通過異步方法進行異步調用。
似乎https://restcountries.eu (我向其發送請求的其余服務器沒有響應)
當使用其他http://countryapi.gear.host等其他服務器時,我的代碼(原始)可以正常工作。
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