Randomizing rows – C#

In earlier post we have seen how we can randomize rows using sql server function “NewId()”.

 Now we will explore way of randomizing rows in C# after retrieving them from database.

I am writing a console application to illustrate the concept

My console application contain a class for generating random number, in main program class I have a function to get dataset “GetDataSet” that emulate fetching data from SQL server using ADO.NET .

The Idea is to add one more row into retrieved record set and put random number value there ,then based on this column sorting whole datatable.

   I am using LINQ to achieve it.       

Below is complete code for the same.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Data;

using System.Data.SqlClient;

using System.Threading;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            DataSet ds = GetDataSet();

             //Copying A Schema of Existing Result Reset and adding one more column to 

            //save randomly generated number

            DataTable Mydt = new DataTable();

            Mydt = ds.Tables[0].Clone();

            Mydt.Columns.Add("Randomizer", typeof(Int32));

            //Generate specfied number of brandom numbers

            var RandomList = RandomProvider.GetRandomSequence(100, ds.Tables[0].Rows.Count).ToList();

           

            //used to keep track of row number in linq query

            int i=0;

            //doing linq operations on datarow collection

             IEnumerable<DataRow> results =(

                                            from

                                                row

                                            in

                                                ds.Tables["ExampleDt"].AsEnumerable()

                                            select

                                                 Mydt.Rows.Add(

                                                                new Object[] {

                                                                                row["Id"].ToString(),

                                                                                row["Name"].ToString(),

                                                                                row["City"].ToString(),

                                                                                row["Company"].ToString(),

                                                                                RandomList[i++]

                                                                             }

                                                               )

                                            ).ToList().OrderBy(x => x.Field<Int32>("Randomizer"));

            //Final Output

             Mydt = results.CopyToDataTable();

        }

       

        public static DataSet GetDataSet()

        {

            DataSet ds = new DataSet();

            DataTable dt = new DataTable("ExampleDt");

            dt.Columns.Add("Id", typeof(int));

            dt.Columns.Add("Name", typeof(string));

            dt.Columns.Add("City", typeof(string));

            dt.Columns.Add("Company", typeof(string));

            DataRow drow1 = dt.NewRow();

            drow1["Id"] = 1;

            drow1["Name"] = "suresh";

            drow1["City"] = "Mumbai";

            drow1["Company"] = "ABC Pvt Ltd.";

            DataRow drow2 = dt.NewRow();

            drow2["Id"] = 2;

            drow2["Name"] = "Ramesh";

            drow2["City"] = "Nagpur";

            drow2["Company"] = "PQR Pvt Ltd.";

            DataRow drow3 = dt.NewRow();

            drow3["Id"] = 3;

            drow3["Name"] = "Jayesh";

            drow3["City"] = "Delhi";

            drow3["Company"] = "LMN Pvt Ltd.";

            DataRow drow4 = dt.NewRow();

            drow4["Id"] = 4;

            drow4["Name"] = "Mahesh";

            drow4["City"] = "Banglore";

            drow4["Company"] = "JKL Pvt Ltd.";

            dt.Rows.Add(drow1);

            dt.Rows.Add(drow2);

            dt.Rows.Add(drow3);

            dt.Rows.Add(drow4);

            ds.Tables.Add(dt);

            return ds;

        }

    }

     public static class RandomProvider

    {

        public static IEnumerable<int>  GetRandomSequence(int maxNumber)

        {

            var random = new Random();

            while (true)

                yield return random.Next(maxNumber);

        }

        public static IEnumerable<int> GetRandomSequence(int maxNumber, int maxCount)

        {

            return GetRandomSequence(maxNumber).Take(maxCount);

        }

    }

}