using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var data = new List<Info>();

        data.Add(new Info() { CaseNum = "123", IsFile = "Yes" });

        data.Add(new Info() { CaseNum = "222", IsFile = "Yes" });

        data.Add(new Info() { CaseNum = "345", IsFile = "No" });

        var moreData = new List<Info>();

        moreData.Add(new Info() { CaseNum = "123", FilePath = "aaaa" });

        moreData.Add(new Info() { CaseNum = "222", FilePath = "bbbb" });

​

        //var path = @"\\10.aa1.22.a33\Images\File";

        //var serverName = path.Substring(2, path.Substring(2).IndexOf(@"\"));

        //Console.WriteLine(serverName);

        //var joinedData = data.Join(moreData, i => i.CaseNum, i=> i.CaseNum, (i, i1) => { i.FilePath = i1.FilePath; return i;});

        var a = from d in data

        join md in moreData on d.CaseNum equals md.CaseNum into ps

        from md in ps.DefaultIfEmpty()

        select new Info { CaseNum = d.CaseNum, FilePath = md == null ? "" : md.FilePath, IsFile = d.IsFile };

        foreach (var j in a.ToList()) {

            Console.WriteLine(string.Format("{0},{1},{2}", j.CaseNum, j.IsFile, j.FilePath));

        }

​

        //var caseNumbers = "'" + string.Join("','", data.Where(x => x.IsFile == "Yes").Select(x => x.CaseNum).ToArray()) + "'";

        //Console.WriteLine(caseNumbers);

    }

    public class Info {

            public string CaseNum {get; set;}

        public string IsFile {get;set;}

                public string FilePath {get;set;}

​

    }

}