異步超時後直接返回，異步超時直接返回
應用場景
異步同時請求多個地址，獲得返回的信息並輸出，排除時間響應太久的以免造成不必要的時間等待。
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1 class Program
2 {
3 static void Main(string[] args)
4 {
5 TaskTest();
6 Console.ReadLine();
7 }
8
9 static async void ddd()
10 {
11 Stopwatch sw = new Stopwatch();
12 sw.Start();
13 List<string> urls = new List<string>() { "http://www.baidu.com", "http://www.360.com" };
14 string a = await DownloadAllAsync(urls);
15
16 Console.WriteLine(a);
17 sw.Stop();
18 Console.WriteLine(sw.ElapsedMilliseconds);
19 Console.ReadLine();
20 }
21 static HttpClient httpClient = new HttpClient();
22 static async Task<string> DownloadAllAsync(IEnumerable<string> urls)
23 {
24
25 var downloads = urls.Select(url => httpClient.GetStringAsync(url));
26 Task<string>[] downloadTasks = downloads.ToArray();
27
28 string[] pages = await Task.WhenAll(downloadTasks);
29
30 return string.Concat(pages);
31 }
32
33 static void TaskTest()
34 {
35 var cts = new CancellationTokenSource(TimeSpan.FromMilliseconds(2000));
36 Task<string> t1 = GetString("http://www.baidu.com");
37 Task<string> t2 = GetString("http://www.360.com");
38 Task<string> t3 = GetString("http://www.github.com");
39
40 Task<string>[] arr = new Task<string>[] { t1, t2, t3 };
41 Task.WaitAll(arr,2000);
42 foreach (var dd in arr)
43 Console.WriteLine(dd.Result.ToString());
44 }
45
46 static async Task<string> GetString(string str)
47 {
48 return await httpClient.GetStringAsync(str);
49
50 }
View Code
源碼
