public int InsertEx(User user)

 {

     int id = -;

     using (OleDbConnection conn = new OleDbConnection(AccessHelper.connectionString))

     {

         conn.Open();

         OleDbCommand cmd = new OleDbCommand { Connection = conn, CommandType = CommandType.Text };

         string commandText =

             $"insert into tb_user (username,userpassword,insdate,dr) values (@username, @userpwd, Date(), 0)";

         List<OleDbParameter> paras = new List<OleDbParameter>

                                      {

                                          new OleDbParameter("username", user.UserName),

                                          new OleDbParameter("userpwd", user.UserPassword)

                                      };

         cmd.CommandText = commandText;

         cmd.Parameters.AddRange(paras.ToArray());

         cmd.ExecuteNonQuery();

         cmd.CommandText = "select @@identity as id";

         cmd.Parameters.Clear();

         id = Convert.ToInt32(cmd.ExecuteScalar());

     }

     return id;

 }