vbnet 加減年,加減日數

Dim dt As DateTime = DateTime.Now
'減
Dim dt2 As DateTime = dt.AddYears(-1) '减去一年
Dim dt3 As DateTime = dt.AddDays(-45) '减去45天
'加

Dim dt2 As DateTime = dt.AddYears(1) '加一年 

Dim dt3 As DateTime = dt.AddDays(45) '加45天