Question

我在.NET Universal应用程序中使用Parse API。我已将Parse库添加到PCL，然后将.NET WinRT库与实际的Windows RT项目一起包含在内。以下是我的服务电话。

public async Task<IEnumerable<BasicTask>> GetTasksAsync()
{
    ParseQuery<ParseObject> query = ParseObject.GetQuery(typeof(BasicTask).Name);
    IEnumerable<ParseObject> parseObjects = await query.FindAsync();

    // Convert the parse objects returned from the cloud into our local model representation.
    // We do this in order order to maintain support for the model across multiple cloud services
    // instead of restricting ourselves to the entire app using ParseCloud only.
    return parseObjects.Select(po => this.ConvertParseObjectToDutyTask(po));
}

此方法适用于以下单元测试：

[TestMethod]
public async Task TaskService_GetTasks_HasValue()
{
    var service = new ParseCloudTaskService();

    var tasks = await service.GetTasksAsync();

    Debug.WriteLine(string.Format("{0} tasks found.", tasks.Count()));
}

我从Parse收回所有记录（仅1个大气压）。

当我在Windows App Store应用程序中使用相同的方法时，出现The remote name could not be resolved: 'api.parse.com'异常。目前，我在我的Page load事件中调用它。事件处理程序在我的视图模型中调用Intialize方法，该方法向存储库请求所有任务。存储库从服务中获取任务并将其返回。

网页

private async void pageRoot_Loaded(object sender, Windows.UI.Xaml.RoutedEventArgs e)
{
    if (!(this.DataContext is MainPageViewModel))
    {
        return;
    }
    var vm = this.DataContext as MainPageViewModel;
    await vm.Initialize();

    this.TasksList.ItemsSource = vm.Tasks;
}

查看模型

public async Task Initialize()
{
    try
    {
        IEnumerable<BasicTask> tasks = await this.repository.GetTasksAsync();
        this.tasks = new ObservableCollection<BasicTask>(tasks);
    }
    catch (Exception)
    {
        throw;
    } 
}

存储库

    public async Task<IEnumerable<BasicTask>> GetTasksAsync()
    {
        IEnumerable<BasicTask> tasks = await this.service.GetTasksAsync();

        return tasks;
    }

当事件执行时，当serivce调用await query.FindAsnyc()时会抛出异常。

以下是完整的例外情况。

System.Net.Http.HttpRequestException was unhandled by user code
  HResult=-2146233088
  Message=An error occurred while sending the request.
  Source=mscorlib
  StackTrace:
       at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
       at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
       at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
       at Parse.PlatformHooks.<RequestAsync>d__0.MoveNext()
    --- End of stack trace from previous location where exception was thrown ---
       at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
       at Parse.Internal.InternalExtensions.<>c__DisplayClass7`1.<OnSuccess>b__6(Task t)
       at System.Threading.Tasks.ContinuationResultTaskFromTask`1.InnerInvoke()
       at System.Threading.Tasks.Task.Execute()
    --- End of stack trace from previous location where exception was thrown ---
       at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
       at Parse.Internal.InternalExtensions.<>c__DisplayClass7`1.<OnSuccess>b__6(Task t)
       at System.Threading.Tasks.ContinuationResultTaskFromTask`1.InnerInvoke()
       at System.Threading.Tasks.Task.Execute()
    --- 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 Duty.Services.ParseCloud.ParseCloudTaskService.<GetTasksAsync>d__1.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 Duty.Repositories.Tasks.BasicTaskRepository.<GetTasksAsync>d__0.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 Duty.WindowsAppStore.ViewModels.MainPageViewModel.<Initialize>d__0.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.GetResult()
       at Duty.WindowsAppStore.Views.MainPage.<pageRoot_Loaded>d__0.MoveNext()
  InnerException: System.Net.WebException
       HResult=-2146233079
       Message=The remote name could not be resolved: 'api.parse.com'
       Source=System
       StackTrace:
            at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
            at System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar)
       InnerException:

有没有人知道为什么它在单元测试中工作正常，但未能在应用程序内点击服务？我使用异步模式错了吗？我不确定这是否会影响它，因为在调用Parse服务时发生异常。

修改

为了澄清，我有一个WinRT项目引用了Universal PCL存储库和通用PCL服务库。一旦调用await query.FindAsync();，它就会失败。我的单元测试是一个标准的Windows单元测试项目，并引用完全相同的两个PCL库。两者之间的唯一区别是一个是WinRT，一个是标准的Windows单元测试。两者都使用相同的库，并使用异步进行调用。这两个库都针对Windows 8，Windows Phone 8和.NET 4.5

我是否有特殊权限允许我的应用程序允许在WinRT设备上进行网络访问？

任何帮助都会很棒！

Answer 1

我终于解决了这个问题。您必须修改Package.appxmanifest文件以告知设备该应用程序需要出站Internet权限。这解释了为什么单元测试工作而应用没有。

只要我在应用上启用了互联网权限，网络呼叫就成功了，我从Parse返回了数据。我希望框架会抛出InternetCapabilityNotSet异常或其他东西。当没有设置正确的功能时，还有其他任何东西。

无法解析远程名称：＆＃39; api.parse.com＆＃39;

1 个答案: