Read csv file and import its data into List(object) with Linq
 
           var arrTitle = File.ReadAllLines(csvFileFolderPath)
                                .Select(x => x.Split(','))
                                .First();

            List lstUser = File.ReadAllLines(csvFileFolderPath)
                                                .Select(x => x.Split(','))
                                                .Skip(1)
                                                .Select(x =>
                                                     new Users
                                                     {
                                                         USERID = x[0],
                                                         LASTNAME = x[1],
                                                         FIRSTNAME = x[2],
                                                         PASSWORD = x[3]
                                                     }).ToList ();


 Read csv file and import its data into Datatable with Linq

            DataTable dt = new DataTable();

            var c1 = File.ReadAllLines(csvFileFolderPath)
                                    .Select(x => x.Split(','))
                                    .First().ToArray();

            var col = from cl in c1
                        select new DataColumn(cl);

            dt.Columns.AddRange(col.ToArray());

            var tableData = File.ReadAllLines(csvFileFolderPath)
                                .Select(x => x.Split(','))
                                .Skip(1)
                                .ToList();

            (from st in tableData
                    select dt.Rows.Add(st)).ToList();

Class File:

Public class Users
{
      public virtual string USERID { get; set; }
      public virtual string LASTNAME { get; set; }
      public virtual string FIRSTNAME { get; set; }
      public virtual string PASSWORD { get; set; }
}

Group by and Sub group in Linq

Created a result set (Using IBATIS.NET Datamapper technology to load object using Stored Procedure method) as on object.

IList<CLASS1> objReport1 = new List<CLASS1>();

IList<CLASS> objReportBase = DataLayer.MethodName(strParam, 1, "N");

if (objReportBase.Count > 0)

{

               objReportNew = (from p in objReportBase

                                group p by new

                                {

                                    p.USERID,

                                    p.DISPLAYUSERID,

                                    p.LASTNAME,

                                    p.FIRSTNAME

                                } into g

                                orderby g.Key.LASTNAME, g.Key.SUITENAME

                                select new CLASS1

                                {

                                    USERID = g.Key.USERID,

                                    DISPLAYUSERID = g.Key.DISPLAYUSERID,

                                    LASTNAME = g.Key.LASTNAME,

                                    FIRSTNAME = g.Key.FIRSTNAME,

                                   

                                    subPVCs = g.Select(l => new

                                                {

                                                    l.COURSENAME,

                                                    l.MASTEREDDATE,

                                                    l.ASSIGNEDDATE,

                                                    l.MASTEREDSCORE,

                                                }

                                             ).Distinct()

                                }).ToList<CLASS1>();

                objReportBase = null;

}

           

public class BASECLASS

{

        public virtual int USERID { get; set; }

        public virtual string DISPLAYUSERID { get; set; }

        public virtual string LASTNAME { get; set; }

        public virtual string FIRSTNAME { get; set; }

        public virtual string COURSENAME { gets; set; }

        public virtual string MASTEREDDATE { get; set; }

        public virtual string ASSIGNEDDATE { get; set; }

        public virtual string MASTEREDSCORE { get; set; }

}

public class CLASS1

{

        public virtual int USERID { get; set; }

        public virtual string DISPLAYUSERID { get; set; }

        public virtual string LASTNAME { get; set; }

        public virtual string FIRSTNAME { get; set; }

        public virtual IEnumerable subPVCs { get; set; }

}

public class subPVC

{

        public virtual int USERID { get; set; }

        public virtual string COURSENAME { gets; set; }

        public virtual string MASTEREDDATE { get; set; }

        public virtual string ASSIGNEDDATE { get; set; }

        public virtual string MASTEREDSCORE { get; set; }

}