#region 增加
        string username = "66";
        string password = "666";
        MySqlCommand cmd = new MySqlCommand("insert into user set username ='" + username + "'" + ",password='" + password + "'", connect);
        //下面的方法可以防止sql恶意语句注入问题 ,但是为什么u3d动态绑定插入不进数据库？？直接创建项目尝试就可以插入数据库。
        //MySqlCommand cmd = new MySqlCommand("insert into user set username=@un , password=@pwd", connect);
        //cmd.Parameters.AddWithValue("un", username);
        //cmd.Parameters.AddWithValue("pwd", password );
        #endregion