using System;

using MoreLinq;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json; 

​

​

public class Upload

{

    public String TimesheetNumber;

    public int SystemId;

}

​

public class Program

{

    public static void Main()

    {

        List<Upload> raw = new List<Upload> {

            new Upload { TimesheetNumber = "0001", SystemId = 123 },

            new Upload { TimesheetNumber = "0002", SystemId = 123 },

            new Upload { TimesheetNumber = "0003", SystemId = 123 },

            new Upload { TimesheetNumber = "0004", SystemId = 123 },

            new Upload { TimesheetNumber = "0005", SystemId = 123 },

            new Upload { TimesheetNumber = "0006", SystemId = 456 },

            new Upload { TimesheetNumber = "0007", SystemId = 456 },

            new Upload { TimesheetNumber = "0008", SystemId = 456 },

        };

        var timesheetsGroupByNumber = from timesheet in raw

            group timesheet by new {timesheet.SystemId, timesheet.TimesheetNumber};     

        var batchesByTimesheetNumber = timesheetsGroupByNumber.Batch(3);

        // Console.WriteLine(JsonConvert.SerializeObject(raw, Formatting.Indented));

        //Console.WriteLine(JsonConvert.SerializeObject(timesheetsGroupByNumber, Formatting.Indented));

        Console.WriteLine("Number of batches = " + batchesByTimesheetNumber.Count());

        Console.WriteLine("Items in first batch = " + batchesByTimesheetNumber.ElementAt(0).Count());

        Console.WriteLine("Items in second batch = " + batchesByTimesheetNumber.ElementAt(1).Count());

        Console.WriteLine("Items in third batch = " + batchesByTimesheetNumber.ElementAt(2).Count());

        Console.WriteLine(JsonConvert.SerializeObject(batchesByTimesheetNumber, Formatting.Indented));

    }

}