To get gmtplus 8 first get the utc time using touniversaltime and then add 8 hours to it
Now.ToUniversalTime.Addhours(8).ToString("MM/dd/yyyy hh:mm:ss")
Or if you want to convert using time zone try this
TimeZoneInfo.ConvertTime(DateTimeOffset.Now, TimeZoneInfo.FindSystemTimeZoneById("Taipei Standard Time")).ToString.("MM/dd/yyyy hh:mm:ss")
Cheers