using System.Runtime.InteropServices;

public static class NetworkShare
{
    /// <summary>
    /// Connects to the remote share
    /// </summary>
    /// <returns>Null if successful, otherwise error message.</returns>
    public static string ConnectToShare(string uri, string username, string password)
    {
        //Create netresource and point it at the share
        NETRESOURCE nr = new NETRESOURCE();
        nr.dwType = RESOURCETYPE_DISK;
        nr.lpRemoteName = uri;

        //Create the share
        int ret = WNetUseConnection(IntPtr.Zero, nr, password, username, 0, null, null, null);

        //Check for errors
        if (ret == NO_ERROR)
            return null;
        else
            return GetError(ret);
    }

    /// <summary>
    /// Remove the share from cache.
    /// </summary>
    /// <returns>Null if successful, otherwise error message.</returns>
    public static string DisconnectFromShare(string uri, bool force)
    {
        //remove the share
        int ret = WNetCancelConnection(uri, force);

        //Check for errors
        if (ret == NO_ERROR)
            return null;
        else
            return GetError(ret);
    }

    #region P/Invoke Stuff
    [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 WNetCancelConnection(
        string lpName,
        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 = "";
    }

    #region Consts
    const int RESOURCETYPE_DISK = 0x00000001;
    const int CONNECT_UPDATE_PROFILE = 0x00000001;
    #endregion

    #region Errors
    const int NO_ERROR = 0;

    const int ERROR_ACCESS_DENIED = 5;
    const int ERROR_ALREADY_ASSIGNED = 85;
    const int ERROR_BAD_DEVICE = 1200;
    const int ERROR_BAD_NET_NAME = 67;
    const int ERROR_BAD_PROVIDER = 1204;
    const int ERROR_CANCELLED = 1223;
    const int ERROR_EXTENDED_ERROR = 1208;
    const int ERROR_INVALID_ADDRESS = 487;
    const int ERROR_INVALID_PARAMETER = 87;
    const int ERROR_INVALID_PASSWORD = 1216;
    const int ERROR_MORE_DATA = 234;
    const int ERROR_NO_MORE_ITEMS = 259;
    const int ERROR_NO_NET_OR_BAD_PATH = 1203;
    const int ERROR_NO_NETWORK = 1222;
    const int ERROR_SESSION_CREDENTIAL_CONFLICT = 1219;

    const int ERROR_BAD_PROFILE = 1206;
    const int ERROR_CANNOT_OPEN_PROFILE = 1205;
    const int ERROR_DEVICE_IN_USE = 2404;
    const int ERROR_NOT_CONNECTED = 2250;
    const int ERROR_OPEN_FILES = 2401;

    private struct ErrorClass
    {
        public int num;
        public string message;
        public ErrorClass(int num, string message)
        {
            this.num = num;
            this.message = message;
        }
    }

    private static ErrorClass[] ERROR_LIST = new ErrorClass[] {
        new ErrorClass(ERROR_ACCESS_DENIED, "Error: Access Denied"), 
        new ErrorClass(ERROR_ALREADY_ASSIGNED, "Error: Already Assigned"), 
        new ErrorClass(ERROR_BAD_DEVICE, "Error: Bad Device"), 
        new ErrorClass(ERROR_BAD_NET_NAME, "Error: Bad Net Name"), 
        new ErrorClass(ERROR_BAD_PROVIDER, "Error: Bad Provider"), 
        new ErrorClass(ERROR_CANCELLED, "Error: Cancelled"), 
        new ErrorClass(ERROR_EXTENDED_ERROR, "Error: Extended Error"), 
        new ErrorClass(ERROR_INVALID_ADDRESS, "Error: Invalid Address"), 
        new ErrorClass(ERROR_INVALID_PARAMETER, "Error: Invalid Parameter"), 
        new ErrorClass(ERROR_INVALID_PASSWORD, "Error: Invalid Password"), 
        new ErrorClass(ERROR_MORE_DATA, "Error: More Data"), 
        new ErrorClass(ERROR_NO_MORE_ITEMS, "Error: No More Items"), 
        new ErrorClass(ERROR_NO_NET_OR_BAD_PATH, "Error: No Net Or Bad Path"), 
        new ErrorClass(ERROR_NO_NETWORK, "Error: No Network"), 
        new ErrorClass(ERROR_BAD_PROFILE, "Error: Bad Profile"), 
        new ErrorClass(ERROR_CANNOT_OPEN_PROFILE, "Error: Cannot Open Profile"), 
        new ErrorClass(ERROR_DEVICE_IN_USE, "Error: Device In Use"), 
        new ErrorClass(ERROR_EXTENDED_ERROR, "Error: Extended Error"), 
        new ErrorClass(ERROR_NOT_CONNECTED, "Error: Not Connected"), 
        new ErrorClass(ERROR_OPEN_FILES, "Error: Open Files"), 
        new ErrorClass(ERROR_SESSION_CREDENTIAL_CONFLICT, "Error: Credential Conflict"),
    };

    private static string GetError(int errNum)
    {
        foreach (ErrorClass er in ERROR_LIST)
        {
            if (er.num == errNum) return er.message;
        }
        return "Error: Unknown, " + errNum;
    }
    #endregion

    #endregion
}

ConnectToShare(@"\\NombreServidor\Carpeta", username, password);
Test="HOLA"
if (!Directory.Exists(@"\\NombreServidor\Carpeta\"))
    Directory.CreateDirectory(@"\\NombreServidor\Carpeta\"+Test);   
File.Copy("C:\MiCarpeta\archivo.txt", @"\\NombreServidor\Carpeta\");

DisconnectFromShare(@"\\NombreServidor\Carpeta", false);