c# - 如何从日期时间中减去一年零一天？

Question

我看到类似 this 的答案但是如何在此之后添加 1 天？就像 2 年前和 1 天。

var myDate = DateTime.Now;
var newDate = myDate.AddYears(-2);
var NewExpiryDate = myDate.AddDays(-1);
var NewFinalDate = ?

Answer 1

你做错了什么:

myDate 将是当前日期，然后您将 -2 年添加到当前日期并分配给 newDate。这不会更新 myDate 它仍然是当前日期，因此您需要将 -1 天添加到 newDate 以获得所需的输出。您可以像这样使用更简单的方法:

var newDate = myDate.AddYears(-2).AddDays(-1);

Note : The date Functions .AddYears() will not alter the source, it will return a new DateTime that adds the specified number of years to the value of this instance. As Soner said, DateTime is an immutable type Which means is an object whose state cannot be modified after it is created.