减去90天或3个月 [英] Subtracting 90 days or 3 months

问题描述

我想创建一个正好是90的日期.添加天数为负值会给我这个错误:

从字符串"02/09/2011"到类型"Long"的转换无效.

I want to create a date exactly 90 earlier. Add days with a negative value gives me this error:

Conversion from string "02/09/2011" to type ''Long'' is not valid.

New Date(Now.AddDays(-90).ToShortDateString)

推荐答案

出现了什么问题:

What''s wrong with:

Dim dt As Date = Now.AddDays(-90)

?

DateTime.Today.DayOfYear-90

DateTime.Today.DayOfYear - 90

如果您将字符串值分配为日期，则会发生此错误.
Date的构造函数没有采用String格式的Date的.请尝试以下方法:

If you are assigning String Value as a Date then this Error occurs.
There is no constructor for Date which take Date in String format as it is.Try this one :

Dim _Date As Date = New Date("2011", 12, "1")
MessageBox.Show(_Date.Month - 3)

希望对您有帮助. :)

I hope it will help you. :)

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