.net 4.5 异步任务，如何取消？在线等

[a121984376]

 private async void btnRequest_Click(object sender, EventArgs e)
        {
            this.btnRequest.Enabled = false;
            var type = this.dropType.Text;
            var date = this.dateTimePicker1.Value;
            var result = await Task.Run(() =>
            {
                var requester = RequesterFactory.CreateRequester(type, date);
                return requester.Request();

            });
            this.btnRequest.Enabled = true;

            if (result.Result)
            {
                RequestForm form = new RequestForm(result);
                form.ShowDialog();
            }
            else
            {
                MessageBox.Show(result.Message);
            }
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            this.TokenSource.Token.Register(() => MessageBox.Show("1"));
            this.TokenSource.Cancel();
        }

以上代码是一个简单的异步任务，任务去执行网络连接等时间长的请求去了，现在我想增加一个取消的方法，该怎么做呢？

[宝_爸]

private async void Start_Button_Click(object sender, RoutedEventArgs e) { var progressIndicator = new Progress<int>(ReportProgress); cts = new CancellationTokenSource(); try { int x = await UploadPicturesAsync(GenerateTestImages(), progressIndicator, cts.Token); } catch (OperationCanceledException ex) { //Do stuff to handle cancellation } } 然后在其他地方就可以cts.Cancel();了。 全部文章参考: Async in 4.5: Enabling Progress and Cancellation in Async APIs http://blogs.msdn.com/b/dotnet/archive/2012/06/06/async-in-4-5-enabling-progress-and-cancellation-in-async-apis.aspx