Formatted Sequence Number

CommonHelper.cs

// db = Instance of Entities Object

public static void StoreLastSequence(int lastSequence, string prefix)
{
  applicationoption applicationoption = db.applicationoption.Where(m => m.CODE == "NOMOR_INVOICE").Single();
  applicationoption.VALUE = lastSequence.ToString();
  db.Entry(applicationoption).State = System.Data.EntityState.Modified;
  db.SaveChanges();
}

public static string[] GetNextSequenceNumber(string prefix)
{
  applicationoption applicationoption = db.applicationoption.Where(m => m.CODE == "NOMOR_INVOICE").Single();
  var today = DateTime.Today;
  int currentSequenceNo = Convert.ToInt32(applicationoption.VALUE);
  currentSequenceNo = currentSequenceNo + 1;

  var formattedSequenceNo = "00000000" + currentSequenceNo.ToString();
  formattedSequenceNo = formattedSequenceNo.Substring(formattedSequenceNo.Length - 7);

  string NextSequence = $"{prefix}{today.Year}{formattedSequenceNo}"; //e.g SYP20190000001, SYP20190000002
  string[] returns = { NextSequence, currentSequenceNo.ToString() };
  return returns;
}

DDL.sql

CREATE TABLE `applicationoption` (
  `CODE` varchar(50) NOT NULL,
  `DESCRIPTION` varchar(200) DEFAULT NULL,
  `VALUE` text
  PRIMARY KEY (`CODE`) USING BTREE
);

INSERT INTO `applicationoption` (`CODE`, `DESCRIPTION`, `VALUE`) VALUES ('NOMOR_INVOICE', 'Sequence Number untuk invoice', '0');

Program.cs

using System;
using System.Text;
					
public class Program
{
	public static void Main()
	{
		string[] NextSequenceNumber =  CommonHelper.GetNextSequenceNumber("SYP");
		
		// Save your generated formatted number
		// ... here
		// db.SaveChanges();
		
    		string SequenceNumber = NextSequenceNumber[0];
		int LastSequenceNumber = Convert.ToInt32(NextSequenceNumber[1]);
    		Console.WriteLine("'{0}'", SequenceNumber);
    		Console.WriteLine("'{0}'", LastSequenceNumber);
		
		// Update Last Sequence Number
		CommonHelper.StoreLastSequence("SYP"); 
		
    
	}
}