IBackgroundTask 类中的任务类型

Question

我想要做

async Task DoSomething()
{
   await SomeAsyncAPI();
}

async void Run()
{
   await DoSomething();
   DoAnother();
}

但 IBackgroundTask 类中不允许使用任务类型。我希望 DoAnother() 在 DoSomething 完成后运行。

Answer 1

您可以使用 awaitableIAsyncAction和WindowsRuntimeSystemExtensions.AsAsyncAction：

public IAsyncAction DoWorkAction()
{
    return DoWorkAsync().AsAsyncAction();
}

internal async Task DoWorkAsync()
{
    await Task.Delay(100);
}

public async void Run(IBackgroundTaskInstance taskInstance)
{
   var deferral = taskInstance.GetDeferral();
   try
   {
      await DoWorkAction();
      DoAnother();
   }
   finally
   {
      deferral.Complete();
   }
}

对于Task<T>，使用IAsyncOperation<T>：

public IAsyncOperation<string> DoMoreWorkAction()
{
    return DoMoreWorkAsync().AsAsyncOperation();
}

internal async Task<string> DoMoreWorkAsync()
{
    await Task.Delay(1000);
    return "Hello";
}

public async void Run(IBackgroundTaskInstance taskInstance)
{
   var deferral = taskInstance.GetDeferral();
   try
   {
      await DoMoreWorkAction();
      DoAnother();
   }
   finally
   {
      deferral.Complete();
   }
}