WebClient默认超时？

Question

I see the post from https://stackoverflow.com/questions/6262547/webclient-timeout-error , it says the default timeout is 100 seconds. But I see the comment from How to change the timeout on a .NET WebClient object says

The default timeout is 100 seconds. Although it seems to run for 30 seconds. – Carter Dec 13 '12 at 16:39

In my program the timeout always about 20 seconds, does anybody know the reason?

Answer 1

I put together a minimal case to test the WebClient class's default timeout.

I published a simple website to my local PC which, upon receiving a request, waits 300 seconds (long enough to make WebClient time out), and then returns a response.

I wrote a simple program which uses a WebClient to make a request to that site, and report what happens:

void Main()
{
    Console.WriteLine("Starting request at " + DateTime.Now);
    WebClient client = new WebClient();
    try
    {
        string response = client.DownloadString("http://slowsite.local/");
        Console.WriteLine("Response returned at " + DateTime.Now);
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.GetType() + " " + ex.Message + " at " + DateTime.Now);
    }
}

The WebClient did time out after 100 seconds . The program produced this output:

Starting request at 8/1/2017 9:31:11 AM
System.Net.WebException The request was aborted: The operation has timed out. at 8/1/2017 9:32:51 AM

The client test program targeted .NET Framework 4.6.