Aadhaar (UDID) Number Validation Using C#

This article describes how to validate UDID number using C# in a client-side C# application. We can validate the Aadhaar number using verhoeff algorithm before sending to the server.

This article describes how to validate a UDID number (similar to the Social Security Number in the US) using C# in a client-side C# application. We can validate the Aadhaar number using a Verhoeff algorithm before sending it to the server.

First design a Windows Form.

 

Back-end Code

private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (textBox1.Text.Length == 4)
            textBox2.Focus();
        }
        private void textBox2_TextChanged(object sender, EventArgs e)
        {
            if (textBox2.Text.Length == 4)
                textBox3.Focus();
            if (textBox2.Text.Length == 0)
                textBox1.Focus();
        }
        private void textBox3_TextChanged(object sender, EventArgs e)
        {
            if (textBox3.Text.Length == 0)
                textBox2.Focus();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            string sAdhaar = textBox1.Text + textBox2.Text + textBox3.Text;
            if (sAdhaar.Length == 12)
            {

                bool isValidnumber = aadharcard.validateVerhoeff(sAdhaar);
                if (isValidnumber)
                {
                    label2.ForeColor = Color.Green;
                    label2.Text = "Aadhaar Validation Success";
                }
                else
                {
                    label2.ForeColor = Color.Red;
                    label2.Text = "Invalid Aadhaar Number";
                }
            }
            else
            {
                label2.Text = "Enter Adhaar Number";
                label2.ForeColor = Color.Red;
            }

        }

Create a new class file with the name aadharcard.cs.

public class aadharcard
  {
      static 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 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 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;

      }
      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;
      }
  }

Result

Invalid Aadhaar Number -

 

Valid Aadhaar Number -