这是整个程序，请高手指教
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.OleDb;//添加OleDb命名空间


namespace CustomerEditor
{
    public partial class Form1 : Form
    {
        //Fields....
        public OleDbConnection _connection;
        public Form1()
        {
            InitializeComponent();
        }

        private void menuDataConnect_Click(object sender, EventArgs e)
        {
            Connect();
        }

        public void Connect()
        {
            if (dialogOpenFile.ShowDialog(this) == DialogResult.OK)
            {
                try
                {
                    string connectionString = string.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};User ID=;Password=;", dialogOpenFile.FileName);
                    OleDbConnection newConnection = new OleDbConnection(connectionString);
                    newConnection.Open();
                    connection = newConnection;
                }
                catch (Exception ex)
                {
                    HandleException("A connection not a mdb", ex);
                }
            }
        }

        public void HandleException(string message, Exception ex)
        {
            MessageBox.Show(this, StringFormat("{0}\n{1}:{2}", message, ex.GetType().ToString, ex.Message));
        }

        public OledDbConnection Connection
        {
          get
            {
                return _connection;
            }
           set
           {
                Disconnect();
                _connection = value;
            }
        }

        public void Disconnect()
        {
            if (_connection != null)
            {
                if (_connection.State != ConnectionState.Closed)
                {
                    _connection.Close();
                    _connection = null;
                }
            }
        }
    }

}

using System.Data.OleDb;

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