I'm checking a URL and start a new task to prevent UI freezing.
Like this:
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest; request.Method = "HEAD"; var response = (HttpWebResponse)await Task.Factory.FromAsync<WebResponse>(request.BeginGetResponse,request.EndGetResponse,null); The point is.. I'm implemented a max time (for example 10 seconds). If the app reach 10 seconds without response, the task must be aborted.
HttpWebRequest does not allow you to easily apply a timeout to asynchronous requests.
I recommend you use the more modern HttpClient:
using (var client = new HttpClient()) { client.Timeout = TimeSpan.FromSeconds(10); var response = await client.SendAsync(new HttpRequestMessage(HttpMethod.Head, url)); } If you are stuck in HttpWebRequest land, then you can use a timer that calls Abort (untested):
static async Task<HttpWebResponse> GetResponseWithTimeoutAsync(this HttpWebRequest request, TimeSpan timeout) { // Start request and timeout var delayTask = Task.Delay(timeout); var requestTask = Task<WebResponse>.Factory.FromAsync(request.BeginGetResponse, request.EndGetResponse, null); var completedTask = await Task.WhenAny(delayTask, requestTask); if (completedTask == delayTask) { request.Abort(); throw new TimeoutException(); } return (HttpWebResponse)(await requestTask); } 
