How to use DataflowBlockOptions.CancellationToken?
How can i use DataflowBlockOptions.CancellationToken
?
If I create an instance BufferBlock
like this:
var queue = new BufferBlock<int>(new DataflowBlockOptions { BoundedCapacity = 5, CancellationToken = _cts.Token });
then using the consumer / producer methods it uses queue
, how can I use its CancellationToken to cancel the cancellation?
eg. in the producer method, how can I check the cancellation token - I didn't find any property to access the token.
EDIT: Example of production / consumption methods:
private static async Task Produce(BufferBlock<int> queue, IEnumerable<int> values)
{
foreach (var value in values)
{
await queue.SendAsync(value);
}
queue.Complete();
}
private static async Task<IEnumerable<int>> Consume(BufferBlock<int> queue)
{
var ret = new List<int>();
while (await queue.OutputAvailableAsync())
{
ret.Add(await queue.ReceiveAsync());
}
return ret;
}
Code to call:
var queue = new BufferBlock<int>(new DataflowBlockOptions { BoundedCapacity = 5, CancellationToken = _cts.Token });
// Start the producer and consumer.
var values = Enumerable.Range(0, 10);
Produce(queue, values);
var consumer = Consume(queue);
// Wait for everything to complete.
await Task.WhenAll(consumer, queue.Completion);
EDIT2:
If I call _cts.Cancel()
, the method Produce
does not cancel and ends without interruption.
source to share
If you want to cancel the processing process, you must pass a token into it, for example:
private static async Task Produce(
BufferBlock<int> queue,
IEnumerable<int> values,
CancellationToken token
)
{
foreach (var value in values)
{
await queue.SendAsync(value, token);
Console.WriteLine(value);
}
queue.Complete();
}
private static async Task<IEnumerable<int>> Consume(BufferBlock<int> queue)
{
var ret = new List<int>();
while (await queue.OutputAvailableAsync())
{
ret.Add(await queue.ReceiveAsync());
}
return ret;
}
static void Main(string[] args)
{
var cts = new CancellationTokenSource();
var queue = new BufferBlock<int>(new DataflowBlockOptions { BoundedCapacity = 5, CancellationToken = cts.Token });
// Start the producer and consumer.
var values = Enumerable.Range(0, 100);
Produce(queue, values, cts.Token);
var consumer = Consume(queue);
cts.Cancel();
try
{
Task.WaitAll(consumer, queue.Completion);
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
foreach (var i in consumer.Result)
{
Console.WriteLine(i);
}
Console.ReadKey();
source to share