C# 处理Windows 8.1应用程序中的长异步操作和频繁事件

考虑以下几点：

  void event_handler(object sender, ...){
     DoSomething();
  }

  void DoSomething(){
     // change some page's state 
     // change some page's private members
     var someData = await LongOperation();
     // change some page's state 
     // change some page's private members
  }

现在，我想要以下行为：如果在前一个LongOperation（）尚未完成时触发事件处理程序，则必须取消这样一个LongOperation（）

---

最简单和首选的方法是什么？

最好通过

取消令牌来处理取消：

private CancellationTokenSource _cts;
async void event_handler()
{
  if (_cts != null)
    _cts.Cancel();
  _cts = new CancellationTokenSource();
  await DoSomethingAsync();
}

async Task DoSomethingAsync()
{
  // change some page's state 
  // change some page's private members
  var someData = await LongOperationAsync(_cts.Token);
  // change some page's state 
  // change some page's private members
}

有多种优化，例如，如果以前的操作未取消，则重用以前的
CancellationTokenSource
，等等。但此代码说明了一般原则。
取消最好通过
CancellationToken
处理：

private CancellationTokenSource _cts;
async void event_handler()
{
  if (_cts != null)
    _cts.Cancel();
  _cts = new CancellationTokenSource();
  await DoSomethingAsync();
}

async Task DoSomethingAsync()
{
  // change some page's state 
  // change some page's private members
  var someData = await LongOperationAsync(_cts.Token);
  // change some page's state 
  // change some page's private members
}

有多种优化，例如，如果以前的操作未取消，则重用以前的
CancellationTokenSource
，等等。但此代码说明了一般原则。
取消最好通过
CancellationToken
处理：

private CancellationTokenSource _cts;
async void event_handler()
{
  if (_cts != null)
    _cts.Cancel();
  _cts = new CancellationTokenSource();
  await DoSomethingAsync();
}

async Task DoSomethingAsync()
{
  // change some page's state 
  // change some page's private members
  var someData = await LongOperationAsync(_cts.Token);
  // change some page's state 
  // change some page's private members
}

有多种优化，例如，如果以前的操作未取消，则重用以前的
CancellationTokenSource
，等等。但此代码说明了一般原则。
取消最好通过
CancellationToken
处理：

private CancellationTokenSource _cts;
async void event_handler()
{
  if (_cts != null)
    _cts.Cancel();
  _cts = new CancellationTokenSource();
  await DoSomethingAsync();
}

async Task DoSomethingAsync()
{
  // change some page's state 
  // change some page's private members
  var someData = await LongOperationAsync(_cts.Token);
  // change some page's state 
  // change some page's private members
}

有多种优化，例如，如果先前的操作未被取消，则重用先前的
CancellationTokenSource
，等等。但此代码说明了一般原则