Hi.
I'm trying to cancel an async function before it starts.Well actually it's a loop.
The code is very long so I'm writing the major parts here.
So I have a cancellation token and I set it to true - to cancel.
The loop is like:
Now The try will never work as it seems that the GetHostEntryAsync has already been initiate for every single call in the url list
I can only use it in the exception that , as i see, runs after all the GetHostEntryAsync calls have been initiated.
So long story short, how can I have a cancellation caught before the GetHostEntryAsync ? Is it possible?
Imagine if I have 1000 addresses that I want to iterate and it will only cancel the threads after every one has been tests with GetHostEntryAsync. that would be useless.
I can put a timer but that beats the whole cancellation purpose.
Thanks.
I'm trying to cancel an async function before it starts.Well actually it's a loop.
The code is very long so I'm writing the major parts here.
So I have a cancellation token and I set it to true - to cancel.
The loop is like:
Code:
'url is a list of addresses
Dim downloadTasksQuery As IEnumerable(Of Task(Of String)) =
From url In urlList Select GetIPv4AddressAsync(url, cts.Token)
' goes to function GetIPv4AddressAsync
Async Function (..blah.blah, ct As CancellationToken)
Try
if ct.IsCancellationRequested = true then
exit function
else
iphe = Await System.Net.Dns.GetHostEntryAsync(strHostName)
end if
Catch ex As Exception
if ct.IsCancellationRequested = true then
exit function
else....
end functionI can only use it in the exception that , as i see, runs after all the GetHostEntryAsync calls have been initiated.
So long story short, how can I have a cancellation caught before the GetHostEntryAsync ? Is it possible?
Imagine if I have 1000 addresses that I want to iterate and it will only cancel the threads after every one has been tests with GetHostEntryAsync. that would be useless.
I can put a timer but that beats the whole cancellation purpose.
Thanks.