I have been playing round with the Async CTP
this morning and have a simple program with a button
and a label
. Click the button
and it starts updating the label
, stop the button
it stops writing to the label
. However, I'm not sure how to reset the CancellationTokenSource
so that I can restart the process.
My code:
public partial class MainWindow : Window
{
CancellationTokenSource cts = new CancellationTokenSource();
public MainWindow()
{
InitializeComponent();
button.Content = "Start";
}
async Task DoWork(CancellationToken cancelToken)
{
int i = 0;
while (!cancelToken.IsCancellationRequested)
{
label.Content = i++.ToString();
await TaskEx.Delay(50, cancelToken);
}
}
private void Button_Click(object sender, RoutedEventArgs e)
{
if (button.Content == "Start")
{
button.Content = "Stop";
DoWork(cts.Token);
}
else
{
button.Content = "Start";
cts.Cancel();
}
}
}
You need to recreate the CancellationTokenSource
- there is no way to "reset" this once you set it.
This could be as simple as:
private void Button_Click(object sender, RoutedEventArgs e)
{
if (button.Content == "Start")
{
button.Content = "Stop";
cts.Dispose(); // Clean up old token source....
cts = new CancellationTokenSource(); // "Reset" the cancellation token source...
DoWork(cts.Token);
}
else
{
button.Content = "Start";
cts.Cancel();
}
}