Program.cs

using OnlineStore.Database_Files;
using System;
using System.Windows.Forms;

namespace OnlineStore
{
    static class Program
    {
        
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        

        static void Main()
        {
            // My Online MSQL DataBase
            String connectionStr = "Data Source=SQL5041.site4now.net;Initial Catalog=DB_A5071D_OnlineStore;User Id=DB_A5071D_OnlineStore_admin;Password=01152160972Ah;";
            // Local MSQL DataBase
            //String connectionStr = "Data Source=DESKTOP-JEM2R23\\;Initial Catalog=OnlineStore;Integrated Security=True";

            IConnectionString connectionString = new DataBaseConnection();
            connectionString.SetConnectionString(connectionStr);

            DataBase dataBase = DataBase.GetInstance(connectionString);

            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(mainPage.GetInstance());
        }
    }
}