C# DateTimeOffset Parse Patch

DateTimeOffset 在 Parse 時會使用 Local TimeZone，這會與期望的 TimeZone 產生偏差，需要進行差值修補。

原始碼

1. //TimeZoneInfo.GetSystemTimeZones().Dump(); 
2.  
3. /* (UTC+02:00) 開羅 */ 
4. var zone = TimeZoneInfo.FindSystemTimeZoneById("Egypt Standard Time"); 
5. zone.Dump(); 
6.  
7. var date = DateTimeOffset.Parse("2019-07-01 15:00:00"); 
8. date.Dump(); /* 2019/7/1 下午 03:00:00 +08:00 */ 
9.  
10. var diff = date.Offset - zone.BaseUtcOffset; 
11. diff.Dump(); /* 06:00:00 */ 
12.  
13. date = date.Add(diff); 
14. date.Dump(); /* 2019/7/1 下午 09:00:00 +08:00 */ 
15.  
16. date = TimeZoneInfo.ConvertTime(date, zone); 
17. date.Dump(); /* 2019/7/1 下午 03:00:00 +02:00 */ 

//TimeZoneInfo.GetSystemTimeZones().Dump();

/* (UTC+02:00) 開羅 */
var zone = TimeZoneInfo.FindSystemTimeZoneById("Egypt Standard Time");
zone.Dump();

var date = DateTimeOffset.Parse("2019-07-01 15:00:00");
date.Dump(); /* 2019/7/1 下午 03:00:00 +08:00 */

var diff = date.Offset - zone.BaseUtcOffset;
diff.Dump(); /* 06:00:00 */

date = date.Add(diff);
date.Dump(); /* 2019/7/1 下午 09:00:00 +08:00 */

date = TimeZoneInfo.ConvertTime(date, zone);
date.Dump(); /* 2019/7/1 下午 03:00:00 +02:00 */