使用超时取消静态异步功能

Question

如果需要超过2分钟,我需要取消UpdateDatabase()函数.我已经尝试过canceltokens和计时器,但我无法解决这个问题(找不到任何合适的例子).

你能帮帮我吗？

App.xaml.cs

protected override async void OnLaunched(LaunchActivatedEventArgs args)
{
   await PerformDataFetch();
}

internal async Task PerformDataFetch()
{
   await LocalStorage.UpdateDatabase();
}

LocalStorage.cs

public async static Task<bool> UpdateDatabase()
{
  await ..// DOWNLOAD FILES
  await ..// CHECK FILES
  await ..// RUN CONTROLES
}

根据答案编辑我的课程.

App.xaml.cs保持不变.编辑UpdateDatabase()并在LocalStorage.cs中添加新方法RunUpdate():

public static async Task UpdateDatabase()
{
    CancellationTokenSource source = new CancellationTokenSource();
    source.CancelAfter(TimeSpan.FromSeconds(30)); // how much time has the update process
    Task<int> task = Task.Run(() => RunUpdate(source.Token), source.Token);

    await task;
}

private static async Task<int> RunUpdate(CancellationToken cancellationToken)
{
    cancellationToken.ThrowIfCancellationRequested();
    await ..// DOWNLOAD FILES
    cancellationToken.ThrowIfCancellationRequested();
    await ..// CHECK FILES
    cancellationToken.ThrowIfCancellationRequested();
    await ..// RUN CONTROLES
}

我知道这不是唯一的方法,可能会更好,但对于像我这样的新手来说,这是一个很好的开始.

Answer 1

您需要通过调用将a传递CancellationToken给UpdateDatabase函数并在每次等待之后检查令牌ThrowIfCancellationRequested.看到这个