Validate content of csv file c#

Question

I have a requirement where user will be uploading a csv file in the below format which will contain around 1.8 to 2 million records

SITE_ID,HOUSE,STREET,CITY         


        

Answer 1

Here is one efficient method :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.OleDb;
using System.Text.RegularExpressions;
using System.IO;


namespace ConsoleApplication23
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.csv";
        static void Main(string[] args)
        {
            CSVReader csvReader = new CSVReader();
            DataSet ds = csvReader.ReadCSVFile(FILENAME, true);
            RegexCompare compare = new RegexCompare();
            DataTable errors = compare.Get_Error_Rows(ds.Tables[0]);
        }
    }
    class RegexCompare
    {
        public static Dictionary dict =  new Dictionary() {
               { "SITE_ID", new RegexCompare() { columnName = "SITE_ID", pattern = @"[^\d]+", positveNegative = false, required = true}},
               { "HOUSE", new RegexCompare() { columnName = "HOUSE", pattern = @"[^\d]+", positveNegative = false, required = true}}, 
               { "STREET", new RegexCompare() { columnName = "STREET", pattern = @"[A-Za-z0-9 ]+", positveNegative = true, required = true}}, 
               { "CITY", new RegexCompare() { columnName = "CITY", pattern = @"[A-Za-z ]+", positveNegative = true, required = true}},
               { "STATE", new RegexCompare() { columnName = "STATE", pattern = @"[A-Za-z]{2}", positveNegative = true, required = true}},
               { "ZIP", new RegexCompare() { columnName = "ZIP", pattern = @"\d{5}", positveNegative = true, required = true}},
               { "APARTMENT", new RegexCompare() { columnName = "APARTMENT", pattern = @"\d*", positveNegative = true, required = false}},
            };


        string columnName { get; set;}
        string pattern { get; set; }
        Boolean positveNegative { get; set; }
        Boolean required { get; set; }

        public DataTable Get_Error_Rows(DataTable dt)
        {
            DataTable dtError = null;
            foreach (DataRow row in dt.AsEnumerable())
            {
                Boolean error = false;
                foreach (DataColumn col in dt.Columns)
                {
                    RegexCompare regexCompare = dict[col.ColumnName];
                    object colValue = row.Field