using System;

using System.Collections.Generic;

using System;

using System.Linq;

using System.Xml;                   

using System.Xml.Linq;

using System.Collections; 

using System.Collections.Generic;

using System.Data;

using System.Data.DataSetExtensions;

using System.Data.Linq;

using System.Text;

using System.Text.RegularExpressions;

using System.Xml.Serialization; 

using System.IO;

using System.Globalization;

using System.Diagnostics;

using System.Collections.Concurrent;

using System.Drawing;

public class Program

{

    public static void Main()

    {

        DataTable tableold = new DataTable();

        tableold.Columns.Add("Dosage", typeof(int));

        tableold.Columns.Add("Drug", typeof(string));

        tableold.Columns.Add("Patient", typeof(string));

        tableold.Columns.Add("Date", typeof(DateTime));

        // Here we add five DataRows.

        tableold.Rows.Add(25, "Indocin", "David", DateTime.Now);

        tableold.Rows.Add(50, "Enebrel", "Sam", DateTime.Now);

        tableold.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now);

        tableold.Rows.Add(21, "Combivent", "Janet", DateTime.Now);

        tableold.Rows.Add(100, "Dilantin", "Melanie", DateTime.Now);

        var ids = new List<int>() {25, 50, 10};

        var result = tableold.AsEnumerable()

            .Where(x=> !ids.Contains(x.Field<int>("Dosage")))

            .CopyToDataTable();

        foreach(DataRow r in result.Rows)

        {

            Console.WriteLine(string.Join(",", r.ItemArray));

        }

    }

}