private void btn_add_Click(object sender, EventArgs e)
        {
            try
            {
                Database db = new Database();
                db.openConnection();

                bool test = Validte_Data();
                if (test == true)
                {
                    String cusId = CodeGenerator.generateCustomerID();
                    string query = "INSERT INTO customers VALUES  ('" + cusId + "','" + txt_cus_fname.Text + "', '" + txt_cus_lname.Text + "', '" + txt_cus_NIC.Text + "', '" + txt_cus_mobile.Text + "', '" + txt_cus_addrees_L1.Text + "','" + txt_cus_addrees_L2.Text + "','" + txt_cus_city.Text + "','" + txt_cus_email.Text + "')";

                    db.sqlQuery(query);
                    db.nonQuery();

                    loadData();
                }
                db.getConnection().Close();
            }

            catch (Exception ex)
            {
                MessageBox.Show(Convert.ToString(ex));
            }
        }
        public void loadData()
        {
            Database db = new Database();

            db.openConnection();

            String q1 = "SELECT * FROM customers";

            db.sqlQuery(q1);
            DataTable dt = db.executeQuery();

            bunifuCustomDataGrid1.DataSource = dt;
            db.getConnection().Close();



            for (int i = 0; i < bunifuCustomDataGrid1.Columns.Count; i++)
            {
                bunifuCustomDataGrid1.Columns[i].Visible = false;
            }

            bunifuCustomDataGrid1.Columns[0].Visible    = true;
            bunifuCustomDataGrid1.Columns[0].HeaderText = "ID";
            bunifuCustomDataGrid1.Columns[1].Visible    = true;
            bunifuCustomDataGrid1.Columns[1].HeaderText = "First Name";
            bunifuCustomDataGrid1.Columns[2].Visible    = true;
            bunifuCustomDataGrid1.Columns[2].HeaderText = "Last Name";
            bunifuCustomDataGrid1.Columns[3].Visible    = true;
            bunifuCustomDataGrid1.Columns[3].HeaderText = "NIC";
            bunifuCustomDataGrid1.Columns[7].Visible    = true;
            bunifuCustomDataGrid1.Columns[7].HeaderText = "City";
            bunifuCustomDataGrid1.Columns[4].Visible    = true;
            bunifuCustomDataGrid1.Columns[4].HeaderText = "Mobile";

            btn_update.Visible = false;
            btn_remove.Visible = false;
            btn_add.Enabled    = true;

            clear();
            txt_cus_id.Text = CodeGenerator.generateCustomerID();
        }