[英]Why I can't have more than 5 WebClient.DownloadFileAsync running?
我正在嘗試通過請求許多文件下載來測試另一個應用程序。
所以,我用以下代碼啟動了10個WebClient
實例,但似乎我只能同時運行5個。
class Program
{
public static object locker = new object();
public static void Main(string[] args)
{
for (int i = 0; i < 10; i++)
start(i);
Console.ReadLine();
}
private static void start(object row)
{
DateTime start = DateTime.Now;
WebClient client = new WebClient();
client.Credentials = CredentialCache.DefaultNetworkCredentials;
client.DownloadProgressChanged += (sender, e) => {
lock (locker){
double throughput = e.BytesReceived /
(DateTime.Now - start).TotalSeconds / 1024 / 1024;
double error = 1 - (1 / throughput);
Console.SetCursorPosition(0, (int)row);
Console.WriteLine(
@"({0}) {1:HH\:mm\:ss.ffff} - {2:0.00}Mb - " +
@"{3:##0}% - {4:0.00}Mb/s ({5:+0.00%;-0.00%;0.00%}){6}",
row, DateTime.Now, e.BytesReceived / 1024 / 1024,
e.ProgressPercentage, throughput, error, " ");
}
};
client.DownloadFileAsync(
new Uri("http://site/Download.ashx?Id=123"),
String.Format("c:\\foo_{0}.xxx", row));
}
}
我得到以下輸出:
(0) 14:51:07.1830 - 39,00Mb - 5% - 0,94Mb/s (-6,45%) (1) 14:51:06.8610 - 39,00Mb - 5% - 1,00Mb/s (+0,24%) (2) 14:51:06.5650 - 39,00Mb - 5% - 0,99Mb/s (-1,34%) (3) 14:51:07.2810 - 38,00Mb - 5% - 0,95Mb/s (-5,12%) (4) 14:51:06.5740 - 37,00Mb - 5% - 0,95Mb/s (-5,19%) (5) 14:50:30.4640 - 0,00Mb - 100% - 0,01Mb/s (-12690,64%) (6) 14:50:30.5390 - 0,00Mb - 100% - 0,01Mb/s (-12845,38%) (7) 14:50:30.8380 - 0,00Mb - 100% - 0,01Mb/s (-13909,70%) (8) 14:50:30.6150 - 0,00Mb - 100% - 0,01Mb/s (-12988,80%) (9) 14:50:30.9210 - 0,00Mb - 100% - 0,01Mb/s (-14079,53%)
我可以更改該限制以模擬更多並發用戶嗎?
一個原因可能是,您的服務器(ASP.NET的.ashx擴展名),您只從進程4請求並行下載文件。
您可以在web.config文件中更改此設置。
您需要在配置文件中增加與服務器的最大連接數
<system.net>
<connectionManagement>
<add address=“*“ maxconnection=“100“ />
</connectionManagement>
</system.net>
你是從同一台機器上發射全部10個嗎? 檢查您的事件日志。 當您添加可能存在連接的其他內容時,您可能會遇到強加於XP及以上的TCP / IP的10連接限制。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.