C# Directory.exist always return false on the local network

c#, directory, impersonation, networking

Solution

It's probably an issue connected to user permissions.

From MSDN:

If you do not have at a minimum read-only permission to the directory, the Exists method will return false.

If you're using local account and not domain account, using Directory.Exists() method is problematic.

I had similar problem in the past: I had to check if a net share existed in my network and there was no domain. Your way didn't work for me. In the end, I gave up on Directory.Exists() method and ended up using NET USE command ( http://www.cezeo.com/tips-and-tricks/net-use-command/ )

bool exists = false;
string output = "";
string error = "";

System.Diagnostics.Process process = new System.Diagnostics.Process();
process = new System.Diagnostics.Process();
            ExecuteShellCommand(process, "NET USE", "\""+ @path + "\" "+
               this.password+ " /USER:"+machinename+"\\"+username + " /PERSISTENT:NO",
               ref output, ref error);
Console.WriteLine("\r\n\t__________________________"+
                "\r\n\tOutput:" + output.Trim().Replace("\r", " ") +
                "\r\n\tError: " + error.Trim().Replace("\r"," "));

            if (output.Length>0 && error.Length==0)
            {
                exists = true;
            }

            process = new System.Diagnostics.Process();
            ExecuteShellCommand(process, "NET USE", " /DELETE " + @path,
                ref output, ref error);

....

public void ExecuteShellCommand(System.Diagnostics.Process process, string fileToExecute,
        string command, ref string output, ref string error)
    {
        try
        {
            string CMD = string.Format(System.Globalization.CultureInfo.InvariantCulture, @"{0}\cmd.exe", new object[] { Environment.SystemDirectory });
            string args = string.Format(System.Globalization.CultureInfo.InvariantCulture, "/C {0}", new object[] { fileToExecute });
            if (command != null && command.Length > 0)
            {
                args += string.Format(System.Globalization.CultureInfo.InvariantCulture, " {0}", new object[] { command, System.Globalization.CultureInfo.InvariantCulture });
            }

            System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo(CMD, args);

            startInfo.CreateNoWindow = true;
            startInfo.UseShellExecute = false;
            startInfo.RedirectStandardOutput = true;
            startInfo.RedirectStandardInput = true;
            startInfo.RedirectStandardError = true;

            process.StartInfo = startInfo;

            process.Start();

            // timeout
process.WaitForExit(10 * 1000);
output = process.StandardOutput.ReadToEnd();
             error = process.StandardError.ReadToEnd();
        }
        catch (Win32Exception e32)
        {
            Console.WriteLine("Win32 Exception caught in process: {0}", e32.ToString());
        }
        catch (Exception e
        {
            Console.WriteLine("Exception caught in process: {0}", e.ToString());
        }
        finally
        {
            // close process and do cleanup
            process.Close();
            process.Dispose();
            process = null;
        }
    }

I know it's a hack but it worked for me and it's a possibility. (Although you may need to set up a proper net share)

Problem

I'm trying to check wether a directory exist on not or a local network. After some research on stackoverflow and MSDN, I develop my code by using impersonate method. The problem is it's not working very well, The `Directory.exists()` method always return `False` Here you have my code (it's nearly the same as the one from MSDN): ``` public sealed class SafeTokenHandle : SafeHandleZeroOrMinusOneIsInvalid { private SafeTokenHandle() : base(true) { } [DllImport("kernel32.dll")] [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)] [SuppressUnmanagedCodeSecurity] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool CloseHandle(IntPtr handle); protected override bool ReleaseHandle() { return CloseHandle(handle); } } class Environment { [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)] public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, out SafeTokenHandle phToken); [DllImport("kernel32.dll", CharSet = CharSet.Auto)] public extern static bool CloseHandle(IntPtr handle); const int LOGON32_PROVIDER_DEFAULT = 0; const int LOGON32_LOGON_INTERACTIVE = 2; private void m_SendAlertes() { SafeTokenHandle safeTokenHandle; string v_pathToDir = "\\192.168.1.199\Clients SiteInternet"; if (!LogonUser("RKalculateur", "SERVEUR2", "riskedge", LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, out safeTokenHandle)) { int ret = Marshal.GetLastWin32Error(); throw new System.ComponentModel.Win32Exception(ret); } using (safeTokenHandle) { using (WindowsIdentity newId = new WindowsIdentity(safeTokenHandle.DangerousGetHandle())) { using (WindowsImpersonationContext impersonatedUser = newId.Impersonate()) { if (Directory.Exists(@v_pathToDir)) { // Proceed code here } } } } } } ``` Here you have a picture of the rights for this directory :

Original source

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