validate-aadhar.cs

using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using System;
using System.ComponentModel.DataAnnotations;
using System.Text.RegularExpressions;

namespace HBTU.Attributes
{
    public class Aadhar
    {
        static readonly int[,] d = new int[,]
        {
            {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
            {1, 2, 3, 4, 0, 6, 7, 8, 9, 5},
            {2, 3, 4, 0, 1, 7, 8, 9, 5, 6},
            {3, 4, 0, 1, 2, 8, 9, 5, 6, 7},
            {4, 0, 1, 2, 3, 9, 5, 6, 7, 8},
            {5, 9, 8, 7, 6, 0, 4, 3, 2, 1},
            {6, 5, 9, 8, 7, 1, 0, 4, 3, 2},
            {7, 6, 5, 9, 8, 2, 1, 0, 4, 3},
            {8, 7, 6, 5, 9, 3, 2, 1, 0, 4},
            {9, 8, 7, 6, 5, 4, 3, 2, 1, 0}
        };
        static readonly int[,] p = new int[,]
         {
             {0, 1, 2, 3, 4, 5, 6, 7, 8, 9},
             {1, 5, 7, 6, 2, 8, 3, 0, 9, 4},
             {5, 8, 0, 3, 7, 9, 6, 1, 4, 2},
             {8, 9, 1, 6, 0, 4, 3, 5, 2, 7},
             {9, 4, 5, 3, 1, 2, 6, 8, 7, 0},
             {4, 2, 8, 6, 5, 7, 3, 9, 0, 1},
             {2, 7, 9, 3, 8, 0, 6, 4, 1, 5},
             {7, 0, 4, 6, 9, 1, 3, 2, 5, 8}
         };

        static readonly int[] inv = { 0, 4, 3, 2, 1, 5, 6, 7, 8, 9 };

        public static bool ValidateVerhoeff(string num)
        {
            int c = 0; int[] myArray = StringToReversedIntArray(num);
            for (int i = 0; i < myArray.Length; i++)
            {
                c = d[c, p[(i % 8), myArray[i]]];
            }
            return c == 0;

        }
        public static bool ValidateAadharNumber(String aadharNumber)
        {
            Regex regex = new Regex(@"^\d{4}\s?\d{4}\s?\d{4}$");
            Match match = regex.Match(aadharNumber);
            return match.Success && ValidateVerhoeff(aadharNumber);
        }


        public static string GenerateVerhoeff(string num)
        {
            int c = 0; int[] myArray = StringToReversedIntArray(num);
            for (int i = 0; i < myArray.Length; i++)
            {
                c = d[c, p[((i + 1) % 8), myArray[i]]];
            }
            return inv[c].ToString();
        }

        private static int[] StringToReversedIntArray(string num)
        {
            int[] myArray = new int[num.Length];
            for (int i = 0; i < num.Length; i++)
            {
                myArray[i] = int.Parse(num.Substring(i, 1));
            }
            Array.Reverse(myArray); return myArray;
        }
    }

public class ValidateAadharAttribute : ValidationAttribute
{
    public ValidateAadharAttribute()
    {
    }
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        if (!Aadhar.ValidateAadharNumber(((long)value).ToString()))
        {
            return new ValidationResult("Invalid aadhar number.");
        }

        return ValidationResult.Success;
    }
}
}