2 auto generate number

[lianpiau]

I got a datagridview, when user select a few roll records and insert to another table. So it can insert multiple record at a time.

So I'm provide 2 field with auto generated number to be primary of table.
1 is LoadingNo and another is RecNo.
Therefore, when a batch records(different PO number) insert in one time, so that they have same LoadingNo but different RecNo. The LoadingNo format is yy/MM/0001 and RecNo is 1. and second record can be LoadingNo:11/03/0001 RecNo : 2.

I'm already have LoadingNo Code. Now I want to know how to make the record have same auto generate LoadingNo but different RecNo.

Below are the code for Loading No

private void Form2_Load(object sender, EventArgs e)
        {
            OleDbConnection conAuthor;

            ConnectionStringSettings conSettings = ConfigurationManager.ConnectionStrings["MyDBConnectionString_Loading"];
            string name = conSettings.ProviderName;
            string providerName = conSettings.ProviderName;
            string ConnectionString = conSettings.ConnectionString;

            conAuthor = new OleDbConnection(ConnectionString);

            OleDbCommand command = new OleDbCommand();
            command.Connection = conAuthor;
            command.CommandText = "SELECT  MAX(LoadingNo) AS LoadingNo FROM LoadItem";
            command.CommandType = CommandType.Text;

            conAuthor.Open();
            OleDbDataReader dr = command.ExecuteReader();

            while (dr.Read())
            {
                textBox1.Text = dr["LoadingNo"].ToString();
                
            }

            dr.Close();
            conAuthor.Close();

            string record = textBox1.Text;
            record = CalculateNewRecordNumber(record);

            //let textbox display date format
            textBox2.Text = DateTime.Now.ToShortDateString();
            string strFormat = "dd/MM/yy";
            textBox2.Text = DateTime.Now.ToString(strFormat);

            textBox2.Text = record;

            
        }

        private string CalculateNewRecordNumber(string record)
        {
            string[] data = record.Split('/');
            DateTime currentDate = DateTime.Today;
            int recordYear = int.Parse(data[0]);
            recordYear = int.Parse("20" + recordYear);
            int recordMonth = int.Parse(data[1]);
            if (currentDate.Year == recordYear)
            {
                if (currentDate.Month == recordMonth)
                {
                    //year and month are the same, we only have to increment the number:
                    int number = int.Parse(data[2]);
                    //do the increment of the record number:
                    number++;
                    //create new record:
                    record = recordYear + "/" + recordMonth + "/";
                    string _recNumberOnly = number.ToString();

                    //loop to create 4 digits number!
                    for (int i = 0; i < 4; i++)
                    {
                        if (_recNumberOnly.Length == 4)
                            break;
                        else
                            _recNumberOnly = "0" + _recNumberOnly;
                    }
                    record += _recNumberOnly;
                }
                else
                {
                    //there is a new month!
                    //increment a month (year stays the same) and starts with number 0001:
                    recordMonth++;
                    //record = recordYear + "/" + recordMonth + "/0001";
                    //year and month are the same, we only have to increment the number:
                    int number = int.Parse(data[2]);
                    //do the increment of the record number:
                    number++;
                    //create new record:
                    record = string.Format("{0:yy}", DateTime.Now) + "/" + string.Format("{0:MM}", DateTime.Now) + "/";
                    string _recNumberOnly = number.ToString();

                    //loop to create 4 digits number!
                    for (int i = 0; i < 4; i++)
                    {
                        if (_recNumberOnly.Length == 4)
                            break;
                        else
                            _recNumberOnly = "0" + _recNumberOnly;
                    }
                    record += _recNumberOnly;
                }
            }
            else
            {
                //there is a new year!
                //increment a year and start from month 1 and starts with number 0001:
                recordYear++;
                //record = recordYear + "/01/0001";
                //year and month are the same, we only have to increment the number:
                int number = int.Parse(data[2]);
                //do the increment of the record number:
                number++;
                //create new record:
                record = string.Format("{0:yy}", DateTime.Now) + "/" + string.Format("{0:MM}", DateTime.Now) + "/";
                string _recNumberOnly = number.ToString();

                //loop to create 4 digits number!
                for (int i = 0; i < 4; i++)
                {
                    if (_recNumberOnly.Length == 4)
                        break;
                    else
                        _recNumberOnly = "0" + _recNumberOnly;
                }
                record += _recNumberOnly;
            }
            return record;
        }
    }