How best way to handle TaskCancellationException inside a Semaphore and Loop

Question

I'm having an issue using HttpCLient.GetStringAsync().
I'm using a SemaphoreSlim to limit to one request by time... something like this:
const int MAX_REQUESTS = 1;
var semaphore = new SemaphoreSlim(MAX_REQUESTS);
Func< IEnumerable<City>, Task > getDetailsAsync = async (cities) =>
await semaphore.WaitAsync();
try
foreach (City c in cities)
string result = null;
string url = "MyUrl";
try
using (HttpClient client = new HttpClient() { Timeout = TimeSpan.FromSeconds(5) })
Debug.WriteLine("Consulting: " + c.code);
result = await client.GetStringAsync(url).ConfigureAwait(continueOnCapturedContext: false);
catch (TaskCanceledException e)
Debug.WriteLine("TaskCanceledException: " + e.Message);
catch (Exception ex)
Debug.WriteLine(ex.Message);
if (result != null)
// Save on local Database
catch (Exception ex)
Debug.WriteLine(ex);
finally
semaphore.Release();
var tasks = cList.Select(m => getDetailsAsync(cities));
await Task.WhenAll(tasks.ToArray()).ConfigureAwait(false);
When the user clicks the button, it goes to this code above and gets the response from server.
The problem is that sometimes "TaskCanceledException" is catch... and when this happens, the app has a strange behavior:
apparently,
it doesn't stop running... my indeterminate progress bar keeps running, but I can't interact with anything on screen, like button or pivot swipe.
I made a search on internet and I believe that this may be deadlock.
But how can I handle this exception, to continue the loop to the next city? 
Thanks!!

Answer 1

Hello,
It seems you want to access web url one by one using HttpClient, but sometimes the app will throw TaskCanceledException and you don’t cancel it, is it right? Please correct if I have any misunderstanding.
Can you submit a repro project for test? I have trouble to reproduce your problem. User your OneDrive and share a link here.
Regards,
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