如何以不同的格式格式化 DateTime? [英] How do I format a DateTime in a different format?

问题描述

我有一个字符串表示某种格式的日期，我希望采用不同的格式.有人告诉我使用 DateTime.(Try)ParseExact，所以我做到了:

I have a string representing a date in a certain format, that I wish to format differently. Someone told me to use DateTime.(Try)ParseExact, so I did:

var dateString = "2016-02-26";
var formatString = "dd/MM/yyyy";

var parsedDate = DateTime.ParseExact(dateString, formatString, null);

你看，我想将日期格式化为 dd/MM/yyyy，所以 26/02/2016.但是，此代码会引发 FormatException:

You see, I want to format the date as dd/MM/yyyy, so 26/02/2016. However, this code throws a FormatException:

字符串未被识别为有效的日期时间.

String was not recognized as a valid DateTime.

如何以不同的方式格式化 DateTime?

How can I format a DateTime differently?

推荐答案

首先，DateTimes 没有格式.DateTime 占据一席之地及时和 标志 指示该时刻是否本地、Utc 或 未指定.

First of all, DateTimes have no format. A DateTime holds a moment in time and a flag indicating whether that moment is Local, Utc or Unspecified.

唯一的时刻 DateTime 被格式化，即当您将其值作为字符串输出时.

The only moment a DateTime gets formatted, is when you output its value as a string.

您提供给 (Try)ParseExact 的格式字符串是要解析的日期(时间)字符串的格式.请参阅 MSDN:自定义日期和时间格式字符串 了解如何编写自己的格式字符串.

The format string you provide to (Try)ParseExact is the format that the date(time) string to parse is in. See MSDN: Custom Date and Time Format Strings to learn how you can write your own format string.

因此，您要查找的用于解析该字符串的代码是这样的，再次确保格式字符串与输入日期字符串的格式完全匹配:

So the code you're looking for to parse that string is this, and again, make sure the format string matches the format of the input date string exactly:

var dateString = "2016-02-26";
var formatString = "yyyy-MM-dd";

var parsedDate = DateTime.ParseExact(dateString, formatString, null);

现在 parsedDate 拥有一个 DateTime 值，您可以以所需的格式输出(请注意，您必须对 / 进行转义，因为它将被解释为日期当前文化的分隔符"，如上述 MSDN 链接):

Now parsedDate holds a DateTime value that you can output in your desired format (and note that you'll have to escape the /, as it'll be interpreted as "the date separator character for the current culture", as explained in above MSDN link):

var formattedDate = parsedDate.ToString("dd\/MM\/yyyy");

这将以所需格式格式化日期:

This will format the date in the desired format:

26/02/2016

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