blocks|key|1211589|text|if+(newsStory.WhenAdded.Date+==+DateTime.Today)
{

}
else
{

}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1211590|应该能行得通。|unstyled|1211591|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>if (newsStory.WhenAdded.Date == DateTime.Today)
{

}
else
{

}
</code></pre>

Should do the trick.

blocks|key|1211586|text|if(+newsStory.Date+==+DateTime.Today+)
{
++++//+happened+today
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1211587|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>if( newsStory.Date == DateTime.Today )
{
 // happened today
}
</code></pre>

blocks|key|1211580|text|试一试|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1211581|if+(newsStory.Date+==+DateTime.Now.Date)+
{+/*+Story+happened+today+*/+}
else
{+/*+Story+didn't+happen+today+*/+}|code-block|syntax|javascript|1211582|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try

<pre><code>if (newsStory.Date == DateTime.Now.Date) 
{ /* Story happened today */ }
else
{ /* Story didn't happen today */ }
</code></pre>

blocks|key|1426831|text|我的解决方案是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1426832|private+bool+IsTheSameDay(DateTime+date1,+DateTime+date2)
{
++++return+(date1.Year+==+date2.Year+&&+date1.DayOfYear+==+date2.DayOfYear);
}|code-block|syntax|javascript|1426833|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

My solution:

<pre><code>private bool IsTheSameDay(DateTime date1, DateTime date2)
{
 return (date1.Year == date2.Year &amp;&amp; date1.DayOfYear == date2.DayOfYear);
}
</code></pre>

blocks|key|1426580|text|如果NewsStory也在使用日期，只需比较DateTime属性，就完成了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1426581|然而，这取决于“今天”的实际含义。如果在午夜前不久发布了一些东西，过了一小段时间它就会变得“旧”了。因此，最好的办法是保持故事的确切日期(包括时间，最好是世界协调时)，并检查是否已经过了不到24小时(或其他时间)，这很简单(可以减去日期，得到一个具有TotalHours或TotalDays属性的TimeSpan+)。|1426582|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

If NewsStory was using a DateTime also, just compare the Date property, and you're done.

However, this depends what "today" actually means. If something is posted shortly before midnight, it will be "old" after a short time. So maybe it would be best to keep the exact story date (including time, preferably UTC) and check if less than 24 hours (or whatever) have passed, which is simple (dates can be subtracted, which gives you a TimeSpan with a TotalHours or TotalDays property).

blocks|key|1426864|text|您可以实现DateTime扩展方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1426865|为您的扩展方法创建新类：|1426866|namespace+ExtensionMethods
{
++++public+static+class+ExtensionMethods
++++{
++++++++public+static+bool+IsSameDay(+this+DateTime+datetime1,+DateTime+datetime2+)
++++++++{
++++++++++++return+datetime1.Year+==+datetime2.Year+
++++++++++++++++&&+datetime1.Month+==+datetime2.Month+
++++++++++++++++&&+datetime1.Day+==+datetime2.Day;
++++++++}
++++}
}|code-block|syntax|javascript|1426867|现在，在你的代码中的任何地方，你想在哪里执行这个测试，你应该包括使用：|1426868|using+ExtensionMethods;|1426869|然后，使用扩展方法：|1426870|newsStory.WhenAdded.IsSameDay(DateTime.Now);|1426871|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

You can implement a DateTime extension method.

Create new class for your extension methods:

<pre><code>namespace ExtensionMethods
{
 public static class ExtensionMethods
 {
 public static bool IsSameDay( this DateTime datetime1, DateTime datetime2 )
 {
 return datetime1.Year == datetime2.Year 
 &amp;&amp; datetime1.Month == datetime2.Month 
 &amp;&amp; datetime1.Day == datetime2.Day;
 }
 }
}
</code></pre>

And now, everywhere on your code, where do you want to perform this test, you should include the using:

<pre><code>using ExtensionMethods;
</code></pre>

And then, use the extension method:

<pre><code>newsStory.WhenAdded.IsSameDay(DateTime.Now);
</code></pre>

blocks|key|1426518|text|按照Guillame建议的in+a+comment，比较Date属性的值：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1426519|newStory.Date+==+DateTime.Now.Date|code-block|syntax|javascript|1426520|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/users/143503/guillaume|1|https://stackoverflow.com/questions/1601609/how-to-check-if-two-datetimes-occur-on-the-same-day/1601643#comment1466735_1601609^0|S|4|2|8|0|D|C|1|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]|$9|10|A|11|1|12]]|E|$]]|$1|F|3|G|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]|S|$5|N|O|P|E|$Q|T]]]]

As <a href="https://stackoverflow.com/users/143503/guillaume">Guillame</a> suggested <a href="https://stackoverflow.com/questions/1601609/how-to-check-if-two-datetimes-occur-on-the-same-day/1601643#comment1466735_1601609">in a comment</a>, compare values of <code>Date</code> properties:

<pre><code>newStory.Date == DateTime.Now.Date
</code></pre>

blocks|key|1426801|text|仅供参考，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1426802|newsStory.Date+==+DateTime.Today|offset|length|style|CODE|1426803|将返回与编码相同的比较结果。|1426804|newsStory+==+DateTime.Today|1426805|其中，newsStory是一个DateTime对象|1426806|.NET足够聪明，可以仅根据日期来确定要进行比较，并将其用于内部比较。不确定为什么，而且实际上很难找到这种行为的文档。|1426807|entityMap^0|0|0|W|0|0|0|R|0|3|9|F|8|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@$D|T|E|U|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|V|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|W|8|@$D|X|E|Y|F|G]]|9|@]|A|$]]|$1|L|3|M|5|6|7|Z|8|@$D|10|E|11|F|G]|$D|12|E|13|F|G]]|9|@]|A|$]]|$1|N|3|O|5|6|7|14|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|Q|$]]

FYI,

<code>newsStory.Date == DateTime.Today</code>

will return the same compare result as coding

<code>newsStory == DateTime.Today</code>

where <code>newsStory</code> is a <code>DateTime</code> object

.NET is smart enough to determine you want to compare based on Date only and uses that for the internal Compare. Not sure why, and actually having trouble finding documentation for this behaviour.

blocks|key|1211680|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1211681|newsStory.Date+==+DateTime.Today|code-block|syntax|javascript|1211682|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this:

<pre><code>newsStory.Date == DateTime.Today
</code></pre>

blocks|key|1211835|text|嗯，DateTime有一个"Date“属性，你可以根据它进行比较。但是从文档中可以看出，获取该属性实际上实例化了一个新的datetime，其中的time组件设置为午夜，因此它可能比访问每个单独的组件慢得多，尽管更简洁和更具可读性。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1211836|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

well, DateTime has a "Date" property and you could just compare based on that. But looking at the docs it seems that getting that property actually instantiates a new datetime with the time component set to midnight, so it may very well be slower than accessing each individual component, although much cleaner and more readable.

blocks|key|1211968|text|if+(newsStory.ToShortDateString()+==+DateTime.Today.ToShortDateString())+++++++++++++++++return+"Todtay";|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1211969|entityMap^0|0|2X|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

<code>if (newsStory.ToShortDateString() == DateTime.Today.ToShortDateString())
 return "Todtay";</code>

blocks|key|1211781|text|怎么样|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1211782|if+(newsStory.DayOfYear+==+DateTime.Now.DayOfYear)
{+//+Story+happened+today
}|code-block|syntax|javascript|1211783|但这也将在2008年1月1日和2009年1月1日返回true，这可能是您想要的，也可能不是。|1211784|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

How about 

<pre><code>if (newsStory.DayOfYear == DateTime.Now.DayOfYear)
{ // Story happened today
}
</code></pre>

But this will also return true for 1st January 2008 and 1st January 2009, which may or may not be what you want.

blocks|key|1211676|text|您可以使用DateTime.Now.DayOfYear|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1211677|+if+(newsStory.DayOfYear+==+DateTime.Now.DayOfYear)
+{+//+story+happened+today

+}
+else
+{+//+story+didn't+happen+today

+}|code-block|syntax|javascript|1211678|entityMap^0|5|M|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

you could use <code>DateTime.Now.DayOfYear</code>

<pre><code> if (newsStory.DayOfYear == DateTime.Now.DayOfYear)
 { // story happened today

 }
 else
 { // story didn't happen today

 }
</code></pre>

Is there a better .net way to check if a DateTime has occured 'today' then the code below?

<pre><code>if ( newsStory.WhenAdded.Day == DateTime.Now.Day &amp;&amp;
 newsStory.WhenAdded.Month == DateTime.Now.Month &amp;&amp;
 newsStory.WhenAdded.Year == DateTime.Now.Year )
{ 
 // Story happened today
}
else
{ 
 // Story didn't happen today
}
</code></pre>

How to check if a DateTime occurs today?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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有没有比下面的代码更好的.net方法来检查“今天”是否发生了DateTime？if ( newsStory.WhenAdded.Day == DateTime.Now.Day &&     newsStory.WhenAdded.Month == DateTime.Now.Month &&     newsStory.WhenAdded.Year == DateTime.Now.Year ){  

问如何检查今天是否发生了DateTime？
EN

回答 13

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问如何检查今天是否发生了DateTime？EN

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问如何检查今天是否发生了DateTime？
EN