C# - Accessing Remote File By Using Impersonation

Sometime we may face “Could not create the file” or “Access denied on 'Some file Name' ” or "Unable to copy file. Access to the path is denied"  error while try to access or modify a file on a remote machine. After reviewing the code you find out, that because the current user does not have access on a remote machine.

Now we want to force your application to do some restricted activity by a user that who not having privileges to do. we call this procedure Impersonation.

In General Impersonation is, A person act like another.

Unprivileged user can access remote machine like privileged one by using privileged users credentials.

We can achieve Impersonation in may ways, I`m taking "WNetCancelConnection2" function from  GAC dll ("mpr.dll").

Note:
mpr.dll is a module containing functions used to handle communication between the Windows operating system and the installed network providers.

Download Here or copy and use below Remote Access Helper class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.InteropServices;

using System.ComponentModel;

using System.Net;

namespace SomeNamespace.Utility

{

    public class RemoteAccessHelper

    {

        public class NetworkConnection : IDisposable

        {

            string _networkName;

            public NetworkConnection(string networkName, NetworkCredential credentials)

            {

                _networkName = networkName;

                var netResource = new NetResource()

                {

                    Scope = ResourceScope.GlobalNetwork,

                    ResourceType = ResourceType.Disk,

                    DisplayType = ResourceDisplaytype.Share,

                    RemoteName = networkName

                };

                var result = WNetAddConnection2(

                    netResource,

                    credentials.Password,

                    credentials.UserName,

                    0);

                if (result != 0)

                {

                    throw new Win32Exception(result, "Error connecting to remote share");

                }

            }

            ~NetworkConnection()

            {

                Dispose(false);

            }

            public void Dispose()

            {

                Dispose(true);

                GC.SuppressFinalize(this);

            }

            protected virtual void Dispose(bool disposing)

            {

                WNetCancelConnection2(_networkName, 0, true);

            }

            [DllImport("mpr.dll")]

            private static extern int WNetAddConnection2(NetResource netResource,

                string password, string username, int flags);

            [DllImport("mpr.dll")]

            private static extern int WNetCancelConnection2(string name, int flags,

                bool force);

        }

        [StructLayout(LayoutKind.Sequential)]

        public class NetResource

        {

            public ResourceScope Scope;

            public ResourceType ResourceType;

            public ResourceDisplaytype DisplayType;

            public int Usage;

            public string LocalName;

            public string RemoteName;

            public string Comment;

            public string Provider;

        }

        public enum ResourceScope : int

        {

            Connected = 1,

            GlobalNetwork,

            Remembered,

            Recent,

            Context

        };

        public enum ResourceType : int

        {

            Any = 0,

            Disk = 1,

            Print = 2,

            Reserved = 8,

        }

        public enum ResourceDisplaytype : int

        {

            Generic = 0x0,

            Domain = 0x01,

            Server = 0x02,

            Share = 0x03,

            File = 0x04,

            Group = 0x05,

            Network = 0x06,

            Root = 0x07,

            Shareadmin = 0x08,

            Directory = 0x09,

            Tree = 0x0a,

            Ndscontainer = 0x0b

        }

    }

}

Below i`m describing some piece of code to show, how to use RemoteAccessHelper.cs ?

var oNetworkCredential = 

    new System.Net.NetworkCredential()

    {

        Domain = "domainName",

        UserName = "domainName" + "\\" + "admin login name",

        Password = "admin password"

    };

using (new RemoteAccessHelper.NetworkConnection(@"\\" + "domainName", oNetworkCredential))

{

    String[] sFolderNames = Directory.GetDirectories( "domainName" + "\\FolderName");

    foreach (String sFolderName in sFolderNames)

    {

        string[] sarrZipFiles = Directory.GetFiles(sFolderName, "*.txt");

        foreach (String sFile in sarrZipFiles)

        {

            // Some unprivileged operations

        }

    }

}

Source: Stackoverflow