c# - 用每月的第一天分配变量

Question

我有一个程序，我想为“每月的第一天”分配一个变量。这是我到目前为止所拥有的：

Dim dtToday As DateTime = DateTime.Today 'Sets todays date (04/15/13)
Dim dtYesterday As DateTime = DateTime.Today.AddDays(-1) 'Sets Yesterdays Date (04/14/13)

我想接下来定义“dtFirstOfMonth”。它将每月的第一天设置为“04/01/13”这将根据它运行的日期而改变......

Answer 1

Dim dtFirstOfMonth as DateTime = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1)

Answer 2

您可以从当前日期减去当前日期。然后添加1以获取第一天：

var firstDayOfMonth = DateTime.Today.AddDays(1 - DateTime.Today.Day);

Answer 3

试试下面的方法，它会帮助你...

 Dim dtToday As DateTime = DateTime.Today
 Dim dtFrom As DateTime
 dtFrom = dtToday.AddDays(-(dtToday.Day - 1))