C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlServerCe;
using System.Configuration;
using System.Text.RegularExpressions; 

namespace PFE
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
           MenuPrincipal f = new MenuPrincipal();
            f.Show();
           
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            String connectionString = null;
            try
            {
                connectionString = ConfigurationManager.ConnectionStrings["boutique"].ConnectionString;
            }
            catch (Exception e1)
            {
                Console.WriteLine("Erreur de configuration : {0}", e1.Message);
                return;
            }

            Console.WriteLine("Chaîne de connexion à la base : [{0}]\n", connectionString);
            try
            {
                using (SqlCeConnection connexion = new SqlCeConnection(connectionString))
                {
                    // ouverture connexion
                    connexion.Open();
                    MessageBox.Show("success");

                }
            }

            catch (Exception ex)
            {

                Console.WriteLine("Erreur d'accès à la base de données (" + ex.Message + ")");
            } 
        }
    }
}