格式不同时比较日期时间 [英] Compare datetime when formats different

问题描述

亲爱的你！
我有麻烦了你能帮助我吗?
在我的项目中有比较日期时间.我现在比较datetime和数据库中的datetime.但是当它们的格式不同时，我无法进行比较.
例如:datetime现在具有格式:yyyy/MM/dd和datetime，我所拥有的字符串具有格式:dd/MM/yyyy.
我该如何比较它们?
我尝试执行以下操作:

Dear you!
I have a trouble. Can you help me?
In my project have compare datetime. I compare datetime now and datetime in database. But when they have format different, i cant compare it.
ex: datetime now have format: yyyy/MM/dd and datetime,which i have is a string have format: dd/MM/yyyy.
How way can i compare them?
I tried to do the following:

string Str_d_n=DateTime.Now.ToString("dd/MM/yyyy",DateTimeFormatInfo.InvariantInfo);
DateTime now_date = DateTime.ParseExact(Str_d_n,"dd/MM/yyyy",CultureInfo.InvariantCulture);
 string dateend = ((DateTime)dr["date_ketthuc"]).ToString("dd/MM/yyyy"); // date end.  
 ss_date_end = DateTime.Compare(DateTime.Parse(dateend), now_date );  // compare. <pre><pre

我运行并遇到错误:字符串未被识别为有效的日期时间."
:(.我很期待您的建议.非常感谢.:).

I run and have error: "string was not recognized as a valid datetime."
:(. I''m looking forward to your suggestions. Thank you so much. :).

推荐答案

谢谢！我已修正错误.

Thank all! I fixed error it.

var now_date = DateTime.Now.Date;
DateTime End = DateTime.Parse(dr["date_ketthuc"].ToString());
var dateend = End.Date;// date end.
ss_date_end = DateTime.Compare(dateend, now_date );  // compare.

现在我可以设置日期时间的任何格式，我的项目仍然可以正确运行:D.
祝您圣诞快乐，新年快乐！！！ ^^

Now i can set anything format of datetime, my project still run correct :D.
I wish you a merry christmas and happy new year !!! ^^

比较日期，而不是字符串:

Compare dates, not strings:

DateTime dateend = ((DateTime)dr["date_ketthuc"]);
DateTime.Compare(dateend, DateTime.Now);

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