stopping an async task

[DanBishop]

I have an program that collects blocks of data asynchronously. I have set the timeout to be -1 ( no timeout ).

It all works fine until I come to close the program down. The program will keep running until it gets another block of data. Is there any way of forcing the task to close?

[AdnanZ]

Hi Dan,

I hope you are doing well today! I would like to know how you are programming this. Can you post a portion of your code which highlights the issue?

[DanBishop]

Hi Adnan,

Thanks for your reply. Hopefully this code will make some sense.

I intitially remove the timeout from the task.

protected override void OnTaskCreated(EventArgs e)
{
base.OnTaskCreated(e);
Task.Stream.Timeout = -1;
}

My ReadCompleted function starts an aynchronous read for the next block of data each time it receives one.

void daqTaskComponent1_ReadCompleted(object sender, DaqTaskComponentReadCompletedEventArgs e)
{
short[,] waveforms = e.GetData();
...
// start waiting for the next frame of data.
if (!Disposing) daqTaskComponent1.ReadAsync();
}

The problem I have is when I attempt to close the program. The program will not close down because the task is still waiting for data. The only way I can stop it is to close the program normally then send it some data. I have attempted the following to hopefully shut it down but it has no effect.

protected override void Dispose(bool disposing)
{
if (disposing)
{
Task.Stop();
}

base.Dispose(disposing);
}

[AdnanZ]

Hi Dan,

Why have you removed the timeout from the task? Try this:
1) Have a timeout.
2) Try the following logic:
void OnTaskTimeout (bool disposing)
{ if (!disposing)
    Task.Start();
}

I think that should work fine. Let me know if it does or doesn't. Have a great day!

[DanBishop]

Hi Adnan,

Thanks that worked, although it has introduced me to another problem that the lack of timeout had hidden. Its related to the hardware sending the input so I have a colleague to moan at.

Thanks for your help.

Daniel Bishop