一个小时之前和很多天之前都可以运行。我尝试ping的链接是:
Link to ping
这是form1中的代码:
在尝试执行以下代码行时,位于 nc 类中:
nc = new NetworkConnection();
bool bval = nc.PingConnection(satellite_address);
if (bval)
{
label19.Visible = true;
label19.Text = "Internet Access";
}
else
{
label19.Visible = true;
label19.Text = "No Internet Access";
}
当它试图执行这行代码时:
bool bval = nc.PingConnection(satellite_address);
它将进入 nc
类:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.NetworkInformation;
using System.IO;
using System.Windows.Forms;
namespace mws
{
class NetworkConnection
{
public NetworkConnection()
{
}
public bool PingConnection(string url)
{
bool Result = false;
using (Ping pp = new Ping())
{
byte[] buffer = Encoding.ASCII.GetBytes("samplestring");
int timeout = 120;
try
{
PingReply reply = pp.Send(url, timeout, buffer);
if (reply.Status == IPStatus.Success)
Result = true;
}
catch (Exception)
{
Result = false;
}
}
return Result;
}
}
}
在尝试执行以下代码行时,位于 nc 类中:
PingReply reply = pp.Send(url, timeout, buffer);
程序跳转到catch块并抛出PingException异常:
Ping请求期间发生了异常
接着在Form1中,返回的结果是没有网络访问权限,但实际上网络是通畅的,我可以无障碍地访问该网址。
这是完整的异常信息:
System.Net.NetworkInformation.PingException was caught
HResult=-2146233079
Message=An exception occurred during a Ping request.
Source=System
StackTrace:
at System.Net.NetworkInformation.Ping.Send(String hostNameOrAddress, Int32 timeout, Byte[] buffer, PingOptions options)
at System.Net.NetworkInformation.Ping.Send(String hostNameOrAddress, Int32 timeout, Byte[] buffer)
at mws.NetworkConnection.PingConnection(String url) in d:\C-Sharp\Download File\Downloading-File-Project-Version-012\Downloading File\NetworkConnection.cs:line 33
InnerException: System.Net.Sockets.SocketException
HResult=-2147467259
Message=No such host is known
Source=System
ErrorCode=11001
NativeErrorCode=11001
StackTrace:
at System.Net.Dns.GetAddrInfo(String name)
at System.Net.Dns.InternalGetHostByName(String hostName, Boolean includeIPv6)
at System.Net.Dns.GetHostAddresses(String hostNameOrAddress)
at System.Net.NetworkInformation.Ping.Send(String hostNameOrAddress, Int32 timeout, Byte[] buffer, PingOptions options)
InnerException:
第33行代码是:
PingReply reply = pp.Send(url, timeout, buffer);
为什么会出现这个异常?在过去几年中,我的程序一直在工作,从未遇到过这种情况。
我应该如何处理它?
ping "http://www.sat24.com/image.ashx?country=afis&type=slide&time=&ir=true&index=1&sat="
。它能正常工作吗? - Thomas Weller