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我需要使用相同的HttpClient的实例，我认为造成线程安全问题做不同方法4个HttpClient的请求。让我更多地解释这一点。安全问题，如何解决这个
里面一个Windows Phone应用程序我正在开发有一个“MainViewModel”类。这个类有一个异步方法来从web服务器获取数据并处理响应。 Async方法被命名为'LoadData'。我甚至在这个班，2种异步方法（“ScheduleArrayAsync”和“CurrActivityAsync”），以帮助处理我从服务器获取数据。
从'LoadData'方法我做3 HttpClient请求（这部分工作像魅力），同时处理所有这三个请求的响应，我需要调用'ScheduleArrayAsync'方法。从那里我必须做一个新的HttpClient请求（问题来了）。这最后一个请求将永远不会生成，并且即使在使用try/catch语句时也不会生成错误代码。
是什么让我觉得这是一个线程问题是，如果我将最后HttpClient的请求“LoadData”的方法，只是作为一个测试，它再次工作。
的MainViewModel类： -
public class MainViewModel : INotifyPropertyChanged
{
public MainViewModel()
{
this.Employees = new ObservableCollection<Employee>();
}
public ObservableCollection<Employee> Employees { get; private set; }
private JsonTextWriter jsonW;
private string Owner;
private RequestResponse reqPList;
public bool IsDataLoaded
{
get;
private set;
}
public async void LoadData()
{
var baseUri = new Uri("https://uri/");
await CookieHandler.GetCookies(baseUri); // A separate request to get some cookies
reqPList = new RequestResponse(); // The class that handle the Httpclinet
await reqPList.GetResponse(baseUri, pList); // First request
XmlConvertor.ConvertToXml(reqPList.Response);
var phoneListResponse = XmlConvertor.XmlString;
await reqPList.GetResponse(baseUri, currActiv); // Second request
XmlConvertor.ConvertToXml(reqPList.Response);
var currActivResponse = XmlConvertor.XmlString;
await reqPList.GetResponse(baseUri, sched); // Third request
XmlConvertor.ConvertToXml(reqPList.Response);
var schedResponse = XmlConvertor.XmlString;
//await reqPList.GetSlotInforPOST("154215");
var handler = new DataHandler();
await handler.phoneListHandler(phoneListResponse);
await handler.CurrActivitiesHandler(currActivResponse);
await handler.ScheduleHandler(schedResponse);
/// Do some processing included call this line
#region Current activity
CurrActivityAsync(item, handler.currActivitiesJSON);
#endregion
this.IsDataLoaded = true;
}
private async void CurrActivityAsync(JToken token, string jString)
{
// Some processing
}
private async void ScheduleArrayAsync(JToken token, string jString)
{
try
{
// Do some more processing and call the fourth request
if (addedInfo[0].Contains("slotInfo"))
await reqPList.GetSlotInforPOST(addedInfo[1]);
else if (addedInfo[0].Contains("vacationInfo"))
await reqPList.GetVacationSlotInfoPOST(addedInfo[1], addedInfo[2]);
}
catch (Exception exp)
{
var d = exp.Message;
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (null != handler)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
下面是requestResponse则类： -
public class RequestResponse
{
public string Response { get; private set; }
private HttpClient client = new HttpClient(new HttpClientHandler()
{
UseCookies = true,
CookieContainer = CookieHandler.Cookiejar,
AllowAutoRedirect = false,
AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip
});
public async Task<string> GetResponse(Uri baseuri, string uriString)
{
if (client.BaseAddress == null)
{
client.BaseAddress = baseuri;
}
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/xhtml+xml"));
var response = await client.GetAsync(baseuri + uriString);
string webresponse = null;
if (response.IsSuccessStatusCode)
{
var resp = await response.Content.ReadAsByteArrayAsync();
var encode = Encoding.GetEncoding("iso-8859-1");
var respString = encode.GetString(resp, 0, resp.Length - 1);
webresponse = respString;
}
return Response = webresponse;
}
public async Task<string> GetSlotInforPOST(string timeId)
{
/// If the method is called from inside 'LoadData' it works.
/// But if it is called from inside ScheduleArrayAsync, it will break at line marked with //***
try
{
var baseUri = new Uri("https://uri/");
const string slotInfo = "cgi-bin/slotInfo.pl";
if (client.BaseAddress == null)
client.BaseAddress = baseUri;
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
HttpContent content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string,string>("timeId",timeId)
});
var response = await client.GetAsync(baseUri + slotInfo); // ***
string webresponse;
if (response.IsSuccessStatusCode)
{
var respo = await client.PostAsync(baseUri + slotInfo, content);
var resp = await respo.Content.ReadAsByteArrayAsync();
var encode = Encoding.GetEncoding("iso-8859-1");
var respString = encode.GetString(resp, 0, resp.Length - 1);
webresponse = respString;
}
}
catch (Exception exp)
{
var s = exp.Message;
}
return Response;
}
public async Task<string> GetVacationSlotInfoPOST(string vacationId, string date)
{
// Do some HttpClient Request
}
}
我是否了解的问题吗？如何克服它？我真的需要从“ScheduleArrayAsync”从“LoadData”
编辑 使最后HttpClient的请求，而不是只是想提一提，在我的努力来解决这个问题，我的HttpClient的不同实例中的每个方法中RequestResponse类。除了我上面提到的，当我打电话从内部“LoadData”一切法第四请求工作，因为它的目的是，即使它的HttpClient的一个实例。
'使用相同的HttpClient实例'。你为什么这么做？你有没有附加到它？你可以创建一个新的，并没有任何这些问题。 – nvoigt
@nvoigt - 差不多就是我要发布的信:) –
@nvoigt是不是更好的性能明智？我想我在这里读了一些关于这方面的内容： - http://social.msdn.microsoft.com/Forums/en-US/4e12d8e2-e0bf-4654-ac85-3d49b07b50af/best-practice-usage-of-httpclient-for- rest-calls-maximum-throughput？forum = netfxnetcom – DreamNet