using System;

using System.IO;

public class Program

{

    public static void Main()

    {

        string _filesPath = @"\\stfsauto01\Acquiring_com\2_MerchantsFiles\";

        string clientID = "1234";

        string frequency = "";

        string folderPath = _filesPath + sftpSub.ClientID + @"\" + (!String.IsNullOrEmpty(frequency) ? frequency + @"\" : "");

​

​

        //string folderPath = Path.Combine(_filesPath, clientID, (!String.IsNullOrEmpty(frequency)) ? frequency + @"\" : "");

    Console.WriteLine(folderPath);

    }

}