HttpClient上的ObjectDisposedException(ObjectDisposedException on HttpClient)

 我有一个Windows通用项目与多个API调用。 一种方法拒绝工作事件我的其他调用完全像这样工作。 我曾尝试using关键字认为它可以解决问题。 
 
 功能： 
 
public async Task<User> GetNewUser(string user_guid, OAuthTokens OAuth)
{
    String userguidJSON = VALIDJSON_BELIEVE_ME;
    using (var httpClient = new HttpClient())
    {
        httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Authorization", Encrypt(OAuth.Accesstoken));

        using (HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Post, BASE_URL + URL_USERS + "/data"))
        {
            req.Content = new StringContent(userguidJSON, Encoding.UTF8, "application/json");
            await httpClient.SendAsync(req).ContinueWith(respTask =>
            {
                Debug.WriteLine(req.Content.ReadAsStringAsync()); //Error is thrown ono this line
            });
            return null;
        }
    }
}
 
 编辑 
 
public async Task<User> GetNewUser(string user_guid, OAuthTokens OAuth)
{
    String userguidJSON = VALIDJSON_BELIEVE_ME;
    using (var httpClient = new HttpClient())
    {
        httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Authorization", Encrypt(OAuth.Accesstoken));

        using (HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Post, BASE_URL + URL_USERS + "/data"))
        {
            req.Content = new StringContent(userguidJSON, Encoding.UTF8, "application/json");
            await httpClient.SendAsync(req);
            var result = await req.Content.ReadAsStringAsync(); //Cannot access a disposed object. Object name: 'System.Net.Http.StringContent'.
            Debug.WriteLine(result);
            return null;
        }
    }
}
 
 堆栈跟踪 
 
 at System.Net.Http.HttpContent.CheckDisposed()
   at System.Net.Http.HttpContent.ReadAsStringAsync()
   at Roadsmart.Service.RoadsmartService.<GetNewUser>d__2e.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Roadsmart.ViewModel.SettingsPageViewModel.<SetNewProfilePicture>d__1e.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>b__3(Object state)
   at System.Threading.WinRTSynchronizationContext.Invoker.InvokeCore()

I have a Windows Universal Project with multiple API calls. One method refuses to work eventhought my other calls work perfectly like this. I have tried the using keyword thought it would resolve the issue.
 
The function:
 
public async Task<User> GetNewUser(string user_guid, OAuthTokens OAuth)
{
    String userguidJSON = VALIDJSON_BELIEVE_ME;
    using (var httpClient = new HttpClient())
    {
        httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Authorization", Encrypt(OAuth.Accesstoken));

        using (HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Post, BASE_URL + URL_USERS + "/data"))
        {
            req.Content = new StringContent(userguidJSON, Encoding.UTF8, "application/json");
            await httpClient.SendAsync(req).ContinueWith(respTask =>
            {
                Debug.WriteLine(req.Content.ReadAsStringAsync()); //Error is thrown ono this line
            });
            return null;
        }
    }
}
 
EDIT
 
public async Task<User> GetNewUser(string user_guid, OAuthTokens OAuth)
{
    String userguidJSON = VALIDJSON_BELIEVE_ME;
    using (var httpClient = new HttpClient())
    {
        httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Authorization", Encrypt(OAuth.Accesstoken));

        using (HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Post, BASE_URL + URL_USERS + "/data"))
        {
            req.Content = new StringContent(userguidJSON, Encoding.UTF8, "application/json");
            await httpClient.SendAsync(req);
            var result = await req.Content.ReadAsStringAsync(); //Cannot access a disposed object. Object name: 'System.Net.Http.StringContent'.
            Debug.WriteLine(result);
            return null;
        }
    }
}
 
The stacktrace
 
 at System.Net.Http.HttpContent.CheckDisposed()
   at System.Net.Http.HttpContent.ReadAsStringAsync()
   at Roadsmart.Service.RoadsmartService.<GetNewUser>d__2e.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Roadsmart.ViewModel.SettingsPageViewModel.<SetNewProfilePicture>d__1e.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>b__3(Object state)
   at System.Threading.WinRTSynchronizationContext.Invoker.InvokeCore()

原文：https://stackoverflow.com/questions/29369945