Открытие файла на чтения (требующего ввода логина/пароля для доступа к серверу)

public class NetworkShareAccesser : IDisposable
{
    private string _remoteUncName;
    private string _remoteComputerName;
 
    public string RemoteComputerName
    {
        get
        {
            return this._remoteComputerName;
        }
        set
        {
            this._remoteComputerName = value;
            this._remoteUncName = @"\\" + this._remoteComputerName;
        }
    }
 
    public string UserName
    {
        get;
        set;
    }
    public string Password
    {
        get;
        set;
    }
 
    #region Consts
 
    private const int RESOURCE_CONNECTED = 0x00000001;
    private const int RESOURCE_GLOBALNET = 0x00000002;
    private const int RESOURCE_REMEMBERED = 0x00000003;
 
    private const int RESOURCETYPE_ANY = 0x00000000;
    private const int RESOURCETYPE_DISK = 0x00000001;
    private const int RESOURCETYPE_PRINT = 0x00000002;
 
    private const int RESOURCEDISPLAYTYPE_GENERIC = 0x00000000;
    private const int RESOURCEDISPLAYTYPE_DOMAIN = 0x00000001;
    private const int RESOURCEDISPLAYTYPE_SERVER = 0x00000002;
    private const int RESOURCEDISPLAYTYPE_SHARE = 0x00000003;
    private const int RESOURCEDISPLAYTYPE_FILE = 0x00000004;
    private const int RESOURCEDISPLAYTYPE_GROUP = 0x00000005;
 
    private const int RESOURCEUSAGE_CONNECTABLE = 0x00000001;
    private const int RESOURCEUSAGE_CONTAINER = 0x00000002;
 
 
    private const int CONNECT_INTERACTIVE = 0x00000008;
    private const int CONNECT_PROMPT = 0x00000010;
    private const int CONNECT_REDIRECT = 0x00000080;
    private const int CONNECT_UPDATE_PROFILE = 0x00000001;
    private const int CONNECT_COMMANDLINE = 0x00000800;
    private const int CONNECT_CMD_SAVECRED = 0x00001000;
 
    private const int CONNECT_LOCALDRIVE = 0x00000100;
 
    #endregion
 
    #region Errors
 
    private const int NO_ERROR = 0;
 
    private const int ERROR_ACCESS_DENIED = 5;
    private const int ERROR_ALREADY_ASSIGNED = 85;
    private const int ERROR_BAD_DEVICE = 1200;
    private const int ERROR_BAD_NET_NAME = 67;
    private const int ERROR_BAD_PROVIDER = 1204;
    private const int ERROR_CANCELLED = 1223;
    private const int ERROR_EXTENDED_ERROR = 1208;
    private const int ERROR_INVALID_ADDRESS = 487;
    private const int ERROR_INVALID_PARAMETER = 87;
    private const int ERROR_INVALID_PASSWORD = 1216;
    private const int ERROR_MORE_DATA = 234;
    private const int ERROR_NO_MORE_ITEMS = 259;
    private const int ERROR_NO_NET_OR_BAD_PATH = 1203;
    private const int ERROR_NO_NETWORK = 1222;
 
    private const int ERROR_BAD_PROFILE = 1206;
    private const int ERROR_CANNOT_OPEN_PROFILE = 1205;
    private const int ERROR_DEVICE_IN_USE = 2404;
    private const int ERROR_NOT_CONNECTED = 2250;
    private const int ERROR_OPEN_FILES = 2401;
 
    #endregion
 
    #region PInvoke Signatures
 
    [DllImport("Mpr.dll")]
    private static extern int WNetUseConnection(
        IntPtr hwndOwner,
        NETRESOURCE lpNetResource,
        string lpPassword,
        string lpUserID,
        int dwFlags,
        string lpAccessName,
        string lpBufferSize,
        string lpResult
        );
 
    [DllImport("Mpr.dll")]
    private static extern int WNetCancelConnection2(
        string lpName,
        int dwFlags,
        bool fForce
        );
 
    [StructLayout(LayoutKind.Sequential)]
    private class NETRESOURCE
    {
        public int dwScope = 0;
        public int dwType = 0;
        public int dwDisplayType = 0;
        public int dwUsage = 0;
        public string lpLocalName = "";
        public string lpRemoteName = "";
        public string lpComment = "";
        public string lpProvider = "";
    }
 
    #endregion
 
    /// <summary>
    /// Creates a NetworkShareAccesser for the given computer name. The user will be promted to enter credentials
    /// </summary>
    /// <param name="remoteComputerName"></param>
    /// <returns></returns>
    public static NetworkShareAccesser Access(string remoteComputerName)
    {
        return new NetworkShareAccesser(remoteComputerName);
    }
 
    /// <summary>
    /// Creates a NetworkShareAccesser for the given computer name using the given domain/computer name, username and password
    /// </summary>
    /// <param name="remoteComputerName"></param>
    /// <param name="domainOrComuterName"></param>
    /// <param name="userName"></param>
    /// <param name="password"></param>
    public static NetworkShareAccesser Access(string remoteComputerName, string domainOrComuterName, string userName, string password)
    {
        return new NetworkShareAccesser(remoteComputerName,
                                        domainOrComuterName + @"\" + userName,
                                        password);
    }
 
    /// <summary>
    /// Creates a NetworkShareAccesser for the given computer name using the given username (format: domainOrComputername\Username) and password
    /// </summary>
    /// <param name="remoteComputerName"></param>
    /// <param name="userName"></param>
    /// <param name="password"></param>
    public static NetworkShareAccesser Access(string remoteComputerName, string userName, string password)
    {
        return new NetworkShareAccesser(remoteComputerName, 
                                        userName,
                                        password);
    }
 
    private NetworkShareAccesser(string remoteComputerName)
    {
        RemoteComputerName = remoteComputerName;               
 
        this.ConnectToShare(this._remoteUncName, null, null, true);
    }
 
    private NetworkShareAccesser(string remoteComputerName, string userName, string password)
    {
        RemoteComputerName = remoteComputerName;
        UserName = userName;
        Password = password;
 
        this.ConnectToShare(this._remoteUncName, this.UserName, this.Password, false);
    }
 
    private void ConnectToShare(string remoteUnc, string username, string password, bool promptUser)
    {
        NETRESOURCE nr = new NETRESOURCE
        {
            dwType = RESOURCETYPE_DISK,
            lpRemoteName = remoteUnc
        };
 
        int result;
        if (promptUser)
        {
            result = WNetUseConnection(IntPtr.Zero, nr, "", "", CONNECT_INTERACTIVE | CONNECT_PROMPT, null, null, null);
        }
        else
        {
            result = WNetUseConnection(IntPtr.Zero, nr, password, username, 0, null, null, null);
        }
 
        if (result != NO_ERROR)
        {
            throw new Win32Exception(result);
        }
    }
 
    private void DisconnectFromShare(string remoteUnc)
    {
        int result = WNetCancelConnection2(remoteUnc, CONNECT_UPDATE_PROFILE, false);
        if (result != NO_ERROR)
        {
            throw new Win32Exception(result);
        }
    }
 
    /// <summary>
    /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
    /// </summary>
    /// <filterpriority>2</filterpriority>
    public void Dispose()
    {
        this.DisconnectFromShare(this._remoteUncName);
    }
}

using (NetworkShareAccesser.Access(REMOTE_COMPUTER_NAME, DOMAIN, USER_NAME, PASSWORD))
{
    File.Copy(@"C:\Some\File\To\copy.txt", @"\\REMOTE-COMPUTER\My\Shared\Target\file.txt");
}