private void Button_Click_1(object sender, RoutedEventArgs e)

        {

            string dir = Directory.GetCurrentDirectory();

            string strcon="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + dir + "\\db.mdb";

            using (OleDbConnection con = new OleDbConnection(strcon))

            {

                if (con.State != ConnectionState.Open)

                {

                    con.Open();

                }

                

              



              DataSet ds = new DataSet();

              OleDbDataAdapter oda = new OleDbDataAdapter("select * from userinfo",con);

              oda.Fill(ds);

              DataTable table = ds.Tables[0];

              DataRowCollection rows=table.Rows;

              for(int i=0;i<rows.Count;i++){

                  DataRow row = rows[i];

                  string username = (string)row["username"];

                  MessageBox.Show(username);

              }

            }

        }