blocks|key|3148159|text|有意思的。看起来datetime格式不是datetime解析器自然期望的格式之一。看过提要类之后，看起来您不能为解析器注入自己的格式化约定，它们很可能使用特定的模式来验证感觉。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3148160|您可以通过修改culture来更改datetime解析器的行为方式。我以前从来没有这样做过，所以我不能肯定它会工作。|offset|length|3148161|另一种解决方案是首先转换你想要阅读的提要。可能不是最好的，但它可以让你绕过这个问题。|3148162|祝好运。|3148163|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/2h3syy57.aspx^0|0|7|7|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|6|7|W|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

Interesting. It would looks like the datetime formatting is not one of the ones naturally expected by the datetime parser. After looking at the feed classes it does not look like you can inject in your own formatting convention for the parser and they it likely uses a specific scheme for validating the feel. 

You may be able to change how the datetime parser behaves by modifying the <a href="http://msdn.microsoft.com/en-us/library/2h3syy57.aspx" rel="nofollow noreferrer">culture</a>. I have never done it before so I can't say for sure it would work.

Another solution night be to first transform the feed you are trying to read. Likely not the greatest but it could get you around the issue.

Good luck.

blocks|key|3360941|text|RSS2.0格式的联合提要在序列化pubDate和lastBuildDate等元素时利用RFC+822+date-time+specification。不幸的是，RFC822日期-时间规范是一种非常“灵活”的语法，用于表示DateTime的时区组件。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3360942|时区可以用几种方式表示。"UT“是世界时(以前称为”格林威治标准时间“)；"GMT”被允许作为对世界时间的引用。军事标准对每个区域使用单个字符。"Z“是世界时。"A“表示提前一小时，"M”表示提前12小时，"N“表示晚一小时，"Y”表示晚12小时。不使用字母"J“。其余两种形式取自ANSI标准X3.51-1975。一种允许显式地指示与UT的偏移量；另一种使用常用的3字符字符串来指示北美的时区。|3360943|我认为这个问题涉及到如何处理RFC822日期时间值的区域组件。提要格式化程序似乎没有处理使用本地差异来指示时区的日期时间。|style|BOLD|3360944|由于RFC1123扩展了RFC822规范，您可以尝试使用DateTimeFormatInfo.RFC1123Pattern+("r")来处理有问题的日期-时间的转换，或者为RFC822格式的日期编写自己的解析代码。另一种选择是使用第三方框架，而不是System.ServiceModel.Syndication命名空间类。|3360945|似乎有一些支持日期-时间解析的known+issues和Rss20FeedFormatter正在被微软解决。|3360946|entityMap|0|LINK|mutability|MUTABLE|url|http://www.w3.org/Protocols/rfc822/#z28|1|http://msdn.microsoft.com/en-us/library/system.globalization.datetimeformatinfo.rfc1123pattern.aspx|2|http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=325421^0|18|V|0|0|0|Q|2|1A|4|0|S|X|1|0|F|C|2|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]|$1|D|3|E|5|6|7|13|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|14|8|@$A|15|B|16|H|I]|$A|17|B|18|H|I]]|9|@]|C|$]]|$1|J|3|K|5|6|7|19|8|@]|9|@$A|1A|B|1B|1|1C]]|C|$]]|$1|L|3|M|5|6|7|1D|8|@]|9|@$A|1E|B|1F|1|1G]]|C|$]]|$1|N|3|-4|5|6|7|1H|8|@]|9|@]|C|$]]]|O|$P|$5|Q|R|S|C|$T|U]]|V|$5|Q|R|S|C|$T|W]]|X|$5|Q|R|S|C|$T|Y]]]]

RSS 2.0 formatted syndication feeds utilize the <a href="http://www.w3.org/Protocols/rfc822/#z28" rel="noreferrer">RFC 822 date-time specification</a> when serializing elements like pubDate and lastBuildDate. The RFC 822 date-time specification is unfortunately a very 'flexible' syntax for expressing the time-zone component of a DateTime.

Time zone may be indicated in several ways. "UT" is Universal Time (formerly called "Greenwich Mean Time"); "GMT" is permitted as a reference to Universal Time. The military standard uses a single character for each zone. "Z" is Universal Time. "A" indicates one hour earlier, and "M" indicates 12 hours earlier; "N" is one hour later, and "Y" is 12 hours later. The letter "J" is not used. The other remaining two forms are taken from ANSI standard X3.51-1975. One allows explicit indication of the amount of offset from UT; the other uses common 3-character strings for indicating time zones in North America.

I believe the issue involves how the zone component of the RFC 822 date-time value is being processed. The feed formatter appears to not be handling date-times that utilize a local differential to indicate the time zone.

As RFC 1123 extends the RFC 822 specification, you could try using the <a href="http://msdn.microsoft.com/en-us/library/system.globalization.datetimeformatinfo.rfc1123pattern.aspx" rel="noreferrer">DateTimeFormatInfo.RFC1123Pattern</a> ("r") to handle converting problamatic date-times, or write your own parsing code for RFC 822 formatted dates. Another option would be to use a third party framework instead of the System.ServiceModel.Syndication namespace classes.

It appears there are some <a href="http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=325421" rel="noreferrer">known issues</a> with date-time parsing and the Rss20FeedFormatter that are in the process of being addressed by Microsoft.

blocks|key|359579|text|基于bug+report+to+Microsoft+about+this中发布的变通方法，我制作了一个XmlReader，专门用于读取具有非标准日期的SyndicationFeeds。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|359580|下面的代码与Microsoft站点上的解决方法中的代码略有不同。它还采用了使用RFC1123模式的Oppositional's+advice。|359581|您需要从一个流创建XmlReader，而不是简单地调用XmlReader.Create()。我使用WebClient类来获取该流：|359582|WebClient+client+=+new+WebClient();
using+(XmlReader+reader+=+new+SyndicationFeedXmlReader(client.OpenRead(feedUrl)))
{
++++SyndicationFeed+feed+=+SyndicationFeed.Load(reader);
++++....
++++//do+things+with+the+feed
++++....
}|code-block|syntax|javascript|359583|以下是SyndicationFeedXmlReader的代码：|359584|public+class+SyndicationFeedXmlReader+:+XmlTextReader
{
++++readonly+string[]+Rss20DateTimeHints+=+{+"pubDate"+};
++++readonly+string[]+Atom10DateTimeHints+=+{+"updated",+"published",+"lastBuildDate"+};
++++private+bool+isRss2DateTime+=+false;
++++private+bool+isAtomDateTime+=+false;

++++public+SyndicationFeedXmlReader(Stream+stream)+:+base(stream)+{+}

++++public+override+bool+IsStartElement(string+localname,+string+ns)
++++{
++++++++isRss2DateTime+=+false;
++++++++isAtomDateTime+=+false;

++++++++if+(Rss20DateTimeHints.Contains(localname))+isRss2DateTime+=+true;
++++++++if+(Atom10DateTimeHints.Contains(localname))+isAtomDateTime+=+true;

++++++++return+base.IsStartElement(localname,+ns);
++++}

++++public+override+string+ReadString()
++++{
++++++++string+dateVal+=+base.ReadString();

++++++++try
++++++++{
++++++++++++if+(isRss2DateTime)
++++++++++++{
++++++++++++++++MethodInfo+objMethod+=+typeof(Rss20FeedFormatter).GetMethod("DateFromString",+BindingFlags.NonPublic+%7C+BindingFlags.Static);
++++++++++++++++Debug.Assert(objMethod+!=+null);
++++++++++++++++objMethod.Invoke(null,+new+object[]+{+dateVal,+this+});

++++++++++++}
++++++++++++if+(isAtomDateTime)
++++++++++++{
++++++++++++++++MethodInfo+objMethod+=+typeof(Atom10FeedFormatter).GetMethod("DateFromString",+BindingFlags.NonPublic+%7C+BindingFlags.Instance);
++++++++++++++++Debug.Assert(objMethod+!=+null);
++++++++++++++++objMethod.Invoke(new+Atom10FeedFormatter(),+new+object[]+{+dateVal,+this+});
++++++++++++}
++++++++}
++++++++catch+(TargetInvocationException)
++++++++{
++++++++++++DateTimeFormatInfo+dtfi+=+CultureInfo.CurrentCulture.DateTimeFormat;
++++++++++++return+DateTimeOffset.UtcNow.ToString(dtfi.RFC1123Pattern);
++++++++}

++++++++return+dateVal;

++++}

}|359585|同样，这几乎完全是从上面链接中的Microsoft站点上发布的解决方法复制的。...except说这个可以为我工作，而在微软发布的那个不行。|359586|注释：您可能需要在类开始时的两个数组中进行一点自定义。根据您的非标准提要可能添加的任何无关字段，您可能需要向这些数组添加更多项。|style|BOLD|359587|entityMap|0|LINK|mutability|MUTABLE|url|https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=325421&wa=wsignin1.0|1|https://stackoverflow.com/questions/210375/problems-reading-rss-with-c-and-net-3-5/263137#263137^0|2|Y|0|0|1D|L|1|0|0|0|0|0|0|0|2|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@$A|17|B|18|1|19]]|C|$]]|$1|D|3|E|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|F|3|G|5|6|7|1E|8|@]|9|@]|C|$]]|$1|H|3|I|5|J|7|1F|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1G|8|@]|9|@]|C|$]]|$1|O|3|P|5|J|7|1H|8|@]|9|@]|C|$K|L]]|$1|Q|3|R|5|6|7|1I|8|@]|9|@]|C|$]]|$1|S|3|T|5|6|7|1J|8|@$A|1K|B|1L|U|V]]|9|@]|C|$]]|$1|W|3|-4|5|6|7|1M|8|@]|9|@]|C|$]]]|X|$Y|$5|Z|10|11|C|$12|13]]|14|$5|Z|10|11|C|$12|15]]]]

Based on the workaround posted in the <a href="https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=325421&amp;wa=wsignin1.0" rel="nofollow noreferrer">bug report to Microsoft about this</a> I made an XmlReader specifically for reading SyndicationFeeds that have non-standard dates. 

The code below is slightly different than the code in the workaround at Microsoft's site. It also takes <a href="https://stackoverflow.com/questions/210375/problems-reading-rss-with-c-and-net-3-5/263137#263137">Oppositional's advice</a> on using the RFC 1123 pattern.

Instead of simply calling XmlReader.Create() you need to create the XmlReader from a Stream. I use the WebClient class to get that stream:

<pre><code>WebClient client = new WebClient();
using (XmlReader reader = new SyndicationFeedXmlReader(client.OpenRead(feedUrl)))
{
 SyndicationFeed feed = SyndicationFeed.Load(reader);
 ....
 //do things with the feed
 ....
}
</code></pre>

Below is the code for the SyndicationFeedXmlReader:

<pre><code>public class SyndicationFeedXmlReader : XmlTextReader
{
 readonly string[] Rss20DateTimeHints = { "pubDate" };
 readonly string[] Atom10DateTimeHints = { "updated", "published", "lastBuildDate" };
 private bool isRss2DateTime = false;
 private bool isAtomDateTime = false;

 public SyndicationFeedXmlReader(Stream stream) : base(stream) { }

 public override bool IsStartElement(string localname, string ns)
 {
 isRss2DateTime = false;
 isAtomDateTime = false;

 if (Rss20DateTimeHints.Contains(localname)) isRss2DateTime = true;
 if (Atom10DateTimeHints.Contains(localname)) isAtomDateTime = true;

 return base.IsStartElement(localname, ns);
 }

 public override string ReadString()
 {
 string dateVal = base.ReadString();

 try
 {
 if (isRss2DateTime)
 {
 MethodInfo objMethod = typeof(Rss20FeedFormatter).GetMethod("DateFromString", BindingFlags.NonPublic | BindingFlags.Static);
 Debug.Assert(objMethod != null);
 objMethod.Invoke(null, new object[] { dateVal, this });

 }
 if (isAtomDateTime)
 {
 MethodInfo objMethod = typeof(Atom10FeedFormatter).GetMethod("DateFromString", BindingFlags.NonPublic | BindingFlags.Instance);
 Debug.Assert(objMethod != null);
 objMethod.Invoke(new Atom10FeedFormatter(), new object[] { dateVal, this });
 }
 }
 catch (TargetInvocationException)
 {
 DateTimeFormatInfo dtfi = CultureInfo.CurrentCulture.DateTimeFormat;
 return DateTimeOffset.UtcNow.ToString(dtfi.RFC1123Pattern);
 }

 return dateVal;

 }

}
</code></pre>

Again, this is copied almost exactly from the workaround posted on the Microsoft site in the link above. ...except that this one works for me, and the one posted at Microsoft did not.

NOTE: One bit of customization you may need to do is in the two arrays at the start of the class. Depending on any extraneous fields your non-standard feed might add, you may need to add more items to those arrays.

blocks|key|3148207|text|类似的问题在.NET+4.0中仍然存在，我决定不直接调用SyndicationFeed.而使用XDocument我描述了应用的方法(特定于我的项目here)。不能说这是最好的解决方案，但它肯定可以被认为是以防SyndicationFeed失败的“后备计划”。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3148208|entityMap|0|LINK|mutability|MUTABLE|url|http://dennisdel.com/?p=342^0|S|F|1B|9|2W|F|21|4|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

A similar problem still persists in .NET 4.0 and I decided to work with XDocument instead of directly invoking SyndicationFeed. I described the applied method (specific to my project <a href="http://dennisdel.com/?p=342" rel="nofollow noreferrer">here</a>). Can't say it is the best solution, but it certainly can be considered a "backup plan" in case SyndicationFeed fails.

I have been attempting to write some routines to read RSS and ATOM feeds using the new routines available in System.ServiceModel.Syndication, but unfortunately the Rss20FeedFormatter bombs out on about half the feeds I try with the following exception:

<blockquote>
<pre><code>An error was encountered when parsing a DateTime value in the XML.
</code></pre>
</blockquote>

This seems to occur whenever the RSS feed expresses the publish date in the following format:

<blockquote>
 Thu, 16 Oct 08 14:23:26 -0700
</blockquote>

If the feed expresses the publish date as GMT, things go fine:

<blockquote>
 Thu, 16 Oct 08 21:23:26 GMT
</blockquote>

If there's some way to work around this with XMLReaderSettings, I have not found it. Can anyone assist?

Problems Reading RSS with C# and .net 3.5

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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我一直在尝试使用System.ServiceModel.Syndication中提供的新例程编写一些例程来读取RSS和ATOM提要，但不幸的是，Rss20FeedFormatter在我尝试的大约一半的提要上失败了，以下是一个例外：在分析XML值时遇到错误。每当RSS提要以以下格式表示发布日期时，似乎就会发生这种情况：清...

问使用C#和.net 3.5时阅读RSS时出现的问题
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