CapDemo.BL.UserBL.AddUser C# (CSharp) Метод

        public bool AddUser(User User)
        {
            string query = "INSERT INTO [User]([Username],[Password])"
                           + "VALUES ('" + User.UserName.Replace("'", "''") + "','" + User.PassWord + "')";
            if (ExistUser(User) == true)
            {
                return false;
            }
            else
            {
                return DA.InsertDatabase(query);
            }
        }