如何检查 UNC 路径是否可用？如果共享不可用，我的问题是检查大约需要半分钟：
var fi = new DirectoryInfo(@"\\hostname\samba-sharename\directory");
if (fi.Exists)
//...
有没有更快的方法来检查文件夹是否可用？我正在使用 Windows XP 和 C#。
问问题
51434 次
7 回答
26
这是一种快速而肮脏的检查方式 - 运行 windowsnet use命令并解析带有感兴趣的网络路径（例如\\vault2）和OK. 这是一个输出示例：
C:\>net use
New connections will be remembered.
Status Local Remote Network
-------------------------------------------------------------------------------
OK O: \\smarty\Data Microsoft Windows Network
Disconnected P: \\dummy\Data Microsoft Windows Network
OK \\vault2\vault2 Microsoft Windows Network
The command completed successfully.
这不是一个非常 .netish 的解决方案，但它非常快，有时更重要:-)。
这是执行此操作的代码（LINQPad 告诉我它只需要150ms，这很好）
void Main()
{
bool available = QuickBestGuessAboutAccessibilityOfNetworkPath(@"\\vault2\vault2\dir1\dir2");
Console.WriteLine(available);
}
public static bool QuickBestGuessAboutAccessibilityOfNetworkPath(string path)
{
if (string.IsNullOrEmpty(path)) return false;
string pathRoot = Path.GetPathRoot(path);
if (string.IsNullOrEmpty(pathRoot)) return false;
ProcessStartInfo pinfo = new ProcessStartInfo("net", "use");
pinfo.CreateNoWindow = true;
pinfo.RedirectStandardOutput = true;
pinfo.UseShellExecute = false;
string output;
using (Process p = Process.Start(pinfo)) {
output = p.StandardOutput.ReadToEnd();
}
foreach (string line in output.Split('\n'))
{
if (line.Contains(pathRoot) && line.Contains("OK"))
{
return true; // shareIsProbablyConnected
}
}
return false;
}
或者您可能会走使用WMI的路线，正如在如何确保网络驱动器已连接到应用程序的答案中所提到的那样？
于 2012-08-02T23:50:14.447 回答
13
在我的项目中，我使用 System.IO ：
if (Directory.Exists(@"\\hostname\samba-sharename\directory")) { ...
到目前为止它非常快......
于 2016-09-28T08:28:00.510 回答
5
在我的一个项目中，我必须检查是否建立了服务器连接。我使用TCP Socket异步检查是否可以访问服务器。我想知道您是否可以使用它来检查网络共享。异步 TCP 套接字连接速度非常快，我在 60 毫秒内对连接进行了 10 次测试。也许你可以玩弄一下？
编辑：这是我用于我的项目的异步套接字。使用此类检查某个 IP 或地址。希望对你有用
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Threading;
namespace Base.BaseObjects
{
public class AsynchronousClient
{
#region Properties
private int _port = 0000, currentTry = 0, _buffersize, _fastpingdelay = 80;
private string _server = "localhost";
private Socket client;
private static IPEndPoint remoteEP;
// Delegates & Events
public delegate void SendMessageDelegate(string message);
public event SendMessageDelegate SendMessageEvent;
public delegate void ConnectionStatusDelegate(bool connected, bool reconnect);
public event ConnectionStatusDelegate ConnectionStatusChanged;
// ManualResetEvent instances signal completion.
private static ManualResetEvent connectDone = new ManualResetEvent(false);
private static ManualResetEvent sendDone = new ManualResetEvent(false);
private static ManualResetEvent receiveDone = new ManualResetEvent(false);
/// <summary>
/// Port to monitor
/// </summary>
public int Port { get { return _port; } }
/// <summary>
/// Number of packages to buffer until system reports connection loss
/// </summary>
public int BufferSize { get { return _buffersize; } }
/// <summary>
/// Time in milliseconds between two pings
/// </summary>
public int FastPingDelay { get { return _fastpingdelay; } }
/// <summary>
/// Servername to connect to
/// </summary>
public string Server
{
get { return _server; }
set
{
_server = value;
// Resolve the remote endpoint for the socket.
try
{
IPAddress ipAddress = (IPAddress)Dns.GetHostAddresses(value)[0];
remoteEP = new IPEndPoint(ipAddress, Port);
}
catch (SocketException ex)
{
SendMessage(ex.Message);
}
}
}
#endregion
#region Events & Delegates
protected void SendMessage(string message)
{
if (SendMessageEvent != null)
SendMessageEvent(message);
}
protected void UpdateConnectionStatus(bool connected, bool reconnect)
{
if (ConnectionStatusChanged != null)
ConnectionStatusChanged(connected, reconnect);
}
private void ConnectCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
SendMessage(String.Format("Socket connected to {0}", client.RemoteEndPoint.ToString()));
//UpdateConnectionStatus(true, false);
// Signal that the connection has been made.
connectDone.Set();
}
catch (Exception e)
{
SendMessage(e.ToString());
UpdateConnectionStatus(false, true);
}
}
#endregion
#region methods
public AsynchronousClient(int port, string server)
{
_port = port;
Server = server;
_buffersize = 10;
_fastpingdelay = 20;
}
public void CreateSocket()
{
try
{
StopClient();
}
catch (Exception ex)
{
SendMessage(ex.Message);
}
finally
{
client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
}
}
public bool FastPingSocket()
{
for (currentTry = 0; currentTry <= BufferSize; currentTry++)
{
try
{
CreateSocket();
client.BeginConnect(remoteEP, new AsyncCallback(ConnectCallback), client);
connectDone.WaitOne();
System.Threading.Thread.Sleep(FastPingDelay);
client.Shutdown(SocketShutdown.Receive);
connectDone.WaitOne();
client.Close();
return true;
}
catch (SocketException ex)
{
SendMessage(ex.Message);
}
catch (ObjectDisposedException ex)
{
currentTry--;
SendMessage(ex.Message);
CreateSocket();
}
catch (NullReferenceException ex)
{
currentTry--;
SendMessage(ex.Message);
CreateSocket();
}
catch (ArgumentNullException ex)
{
SendMessage(ex.Message);
CreateSocket();
}
catch (InvalidOperationException ex)
{
SendMessage(ex.Message);
CreateSocket();
currentTry--;
}
finally
{
StopClient();
}
}
UpdateConnectionStatus(false, true);
return false;
}
public void StopClient()
{
// Release the socket.
try
{
client.Shutdown(SocketShutdown.Both);
client.Close();
}
catch (Exception) { }
finally
{
UpdateConnectionStatus(false, false);
}
}
#endregion
}
}
编辑：请不要只是复制/粘贴它。尝试理解代码，以便您可以将其用于您的利益，并根据您的需要对其进行微调。
于 2011-03-01T10:17:33.727 回答
4
我最终“作弊”并且只是 ping 主机，这是合理的，因为实际上我正在检查的情况就是这样。
private bool HostExists(string PCName)
{
Ping pinger = new Ping();
try
{
PingReply reply = pinger.Send(PCName);
return reply.Status == IPStatus.Success;
}
catch
{
return false;
}
finally
{
pinger.Dispose();
}
}
这种方式最适合我，因为它的速度、简单性和可靠性。
于 2018-12-13T22:32:23.270 回答
3
我使用了上面建议的 ping 方法，但它对我不起作用，因为我使用的是 OpenDNS 下面是一个对我来说效果很好的函数：
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/// <summary>
/// A quick method to test is the path exists
/// </summary>
/// <param name="s"></param>
/// <param name="timeOutMs"></param>
/// <returns></returns>
public static bool CheckPathExists(string s, int timeOutMs = 120) {
if (s.StartsWith(@"\\")) {
Uri uri = new Uri(s);
if (uri.Segments.Length == 0 || string.IsNullOrWhiteSpace(uri.Host))
return false;
if (uri.Host != Dns.GetHostName()) {
WebRequest request;
WebResponse response;
request = WebRequest.Create(uri);
request.Method = "HEAD";
request.Timeout = timeOutMs;
try {
response = request.GetResponse();
} catch (Exception ex) {
return false;
}
return response.ContentLength > 0;
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// Do a Ping to see if the server is there
// This method doesn't work well using OPenDNS since it always succeeds
// regardless if the IP is a valid or not
// OpenDns always maps every host to an IP. If the host is not valid the
// OpenDNS will map it to 67.215.65.132
/* Example:
C:\>ping xxx
Pinging xxx.RT-AC66R [67.215.65.132] with 32 bytes of data:
Reply from 67.215.65.132: bytes=32 time=24ms TTL=55
*/
//Ping pingSender = new Ping();
//PingOptions options = new PingOptions();
// Use the default Ttl value which is 128,
// but change the fragmentation behavior.
//options.DontFragment = true;
// Create a buffer of 32 bytes of data to be transmitted.
//string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
//byte[] buffer = Encoding.ASCII.GetBytes(data);
//int timeout = 120;
//PingReply reply = pingSender.Send(uri.Host, timeout, buffer, options);
//if (reply == null || reply.Status != IPStatus.Success)
// return false;
}
}
return File.Exists(s);
}
于 2013-12-12T21:18:42.077 回答
2
这可能是最快的方法，延迟将是一般网络速度/磁盘访问等。
如果这导致用户延迟，您可以尝试异步检查吗？
于 2011-03-01T09:49:33.977 回答
0
也许您应该尝试创建该文件夹，如果它确实存在，它将返回您可以捕获的错误。不应该有默认超时。
于 2011-03-01T10:15:36.580 回答