blocks|key|447855|text|我听说你想用HtmlAgilityPack来处理HTML文件。这将为您提供Linq访问，使用is+a+Good+Thing+(tm)。您可以使用System.Net.WebClient下载该文件。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|447856|entityMap|0|LINK|mutability|MUTABLE|url|http://htmlagilitypack.codeplex.com/|1|http://msdn.microsoft.com/en-us/library/system.net.webclient.aspx^0|6|F|20|K|6|F|0|20|K|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]|$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]|N|$5|I|J|K|E|$L|O]]]]

I hear you want to use the <a href="http://htmlagilitypack.codeplex.com/" rel="nofollow"><code>HtmlAgilityPack</code></a> for working with HTML files. This will give you Linq access, with is A Good Thing (tm). You can download the file with <a href="http://msdn.microsoft.com/en-us/library/system.net.webclient.aspx" rel="nofollow"><code>System.Net.WebClient</code></a>.

blocks|key|2764219|text|您可以使用Html+Agility+Pack加载html并找到所需的元素。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2764220|entityMap|0|LINK|mutability|MUTABLE|url|http://htmlagilitypack.codeplex.com/^0|5|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

You can use <a href="http://htmlagilitypack.codeplex.com/" rel="nofollow">Html Agility Pack</a> to load html and find the element you need.

blocks|key|2764259|text|要获取超文本标记语言，您可以使用WebClient对象。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2764260|要解析超文本标记语言，可以使用HTMLAgility库。|2764261|entityMap^0|G|9|0|F|B|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

To get the HTML you can use the WebClient object.

To parse the HTML you can use HTMLAgility librrary.

blocks|key|448047|text|首先，您可以相当容易地使用HttpWebRequest来获取URL的内容。在此基础上，您必须执行一些操作来解析出HTML。这就是它开始变得棘手的地方。您不能使用普通的XML解析器，因为有很多(大多数？)网站HTML页面不是100%25有效的XML。Web浏览器已经专门实现了解析器来绕过无效部分。在Ruby语言中，我会使用像Nokogiri这样的东西来解析HTML，所以您可能需要寻找它的.NET端口，或者其他专门为读取HTML而设计的解析器。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|448048|448049|编辑：|448050|因为这个话题很可能会出现：WebClient+vs.+HttpWebRequest/HttpWebResponse|448051|另外，感谢其他回复没有提到HtmlAgility的人。我不知道它的存在。|448052|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx#Y6555|1|http://nokogiri.org/|2|https://stackoverflow.com/questions/1694388/webclient-vs-httpwebrequest-httpwebresponse^0|D|E|0|4G|8|1|0|0|0|D|18|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]|$A|10|B|11|1|12]]|C|$]]|$1|D|3|-4|5|6|7|13|8|@]|9|@]|C|$]]|$1|E|3|F|5|6|7|14|8|@]|9|@]|C|$]]|$1|G|3|H|5|6|7|15|8|@]|9|@$A|16|B|17|1|18]]|C|$]]|$1|I|3|J|5|6|7|19|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]|U|$5|N|O|P|C|$Q|V]]]]

To get you started, you can fairly easily use <a href="http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx#Y6555" rel="nofollow noreferrer">HttpWebRequest</a> to get the contents of a URL. From there, you will have to do something to parse out the HTML. That is where it starts to get tricky. You can't use a normal XML parser, because many (most?) web site HTML pages aren't 100% valid XML. Web browsers have specially implemented parsers to work around the invalid portions. In Ruby, I would use something like <a href="http://nokogiri.org/" rel="nofollow noreferrer">Nokogiri</a> to parse the HTML, so you might want to look for a .NET port of it, or another parser specificly designed to read HTML.

<hr>

Edit:

Since the topic is likely to come up: <a href="https://stackoverflow.com/questions/1694388/webclient-vs-httpwebrequest-httpwebresponse">WebClient vs. HttpWebRequest/HttpWebResponse</a>

Also, thanks to the others that answered for noting HtmlAgility. I didn't know it existed.

blocks|key|4229559|text|研究一下如何使用html+agility+pack，它是解析html的一个比较常用的库。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4229560|http://htmlagilitypack.codeplex.com/|offset|length|4229561|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|10|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@$D|O|E|P|1|Q]]|A|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|C]]]]

Look into using the html agility pack, which is one of the more common libraries for parsing html.

<a href="http://htmlagilitypack.codeplex.com/" rel="nofollow">http://htmlagilitypack.codeplex.com/</a>

blocks|key|818582|text|//+prepare+the+web+page+we+will+be+asking+for
++++++++HttpWebRequest++request++=+(HttpWebRequest)
++++++++++++WebRequest.Create("http://www.stackoverflow.com");

++++++++//+execute+the+request
++++++++HttpWebResponse+response+=+(HttpWebResponse)request.GetResponse();

++++++++//+we+will+read+data+via+the+response+stream
++++++++Stream+resStream+=+response.GetResponseStream();

++++++++string+tempString+=+null;
++++++++int++++count++++++=+0;
++++++++do
++++++++{
++++++++++++//+fill+the+buffer+with+data
++++++++++++count+=+resStream.Read(buf,+0,+buf.Length);

++++++++++++//+make+sure+we+read+some+data
++++++++++++++++if+(count+!=+0)
++++++++++++{
++++++++++++//+translate+from+bytes+to+ASCII+text
++++++++++++tempString+=+Encoding.ASCII.GetString(buf,+0,+count);

++++++++++++//+continue+building+the+string
++++++++++++sb.Append(tempString);
++++++++++++}
++++++++}
++++++++while+(count+>+0);+//+any+more+data+to+read?|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|818583|然后使用Xquery表达式或正则表达式获取所需的元素|unstyled|818584|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>// prepare the web page we will be asking for
 HttpWebRequest request = (HttpWebRequest)
 WebRequest.Create("http://www.stackoverflow.com");

 // execute the request
 HttpWebResponse response = (HttpWebResponse)request.GetResponse();

 // we will read data via the response stream
 Stream resStream = response.GetResponseStream();

 string tempString = null;
 int count = 0;
 do
 {
 // fill the buffer with data
 count = resStream.Read(buf, 0, buf.Length);

 // make sure we read some data
 if (count != 0)
 {
 // translate from bytes to ASCII text
 tempString = Encoding.ASCII.GetString(buf, 0, count);

 // continue building the string
 sb.Append(tempString);
 }
 }
 while (count &gt; 0); // any more data to read?
</code></pre>

Then use Xquery expressions or Regex to grab the element you need

blocks|key|2764399|text|您可以使用System.Net.WebClient或System.Net.HttpWebrequest来获取页面，但是类不支持对元素进行解析。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2764400|使用HtmlAgilityPack+(http://html-agility-pack.net/)|BOLD|2764401|HtmlWeb+htmlWeb+=+new+HtmlWeb();
htmlWeb.UseCookies+=+true;


HtmlDocument+htmlDocument+=+htmlWeb.Load(url);


//+after+getting+the+document+node
//+you+can+do+something+like+this
foreach+(HtmlNode+item+in+htmlDocument.DocumentNode.Descendants("input"))
{+
++++//+item+mathces+your+req
++++//+take+the+item.
}|code-block|syntax|javascript|2764402|entityMap|0|LINK|mutability|MUTABLE|url|http://html-agility-pack.net/^0|5|K|Q|P|0|2|F|J|T|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|10|8|@$9|11|A|12|B|H]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|I|3|J|5|K|7|16|8|@]|D|@]|E|$L|M]]|$1|N|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|O|$P|$5|Q|R|S|E|$T|U]]]]

You could use <code>System.Net.WebClient</code> or <code>System.Net.HttpWebrequest</code> to fetch the page but parsing for the elements is not supported by the classes.

Use HtmlAgilityPack (<a href="http://html-agility-pack.net/" rel="nofollow noreferrer">http://html-agility-pack.net/</a>) 

<pre><code>HtmlWeb htmlWeb = new HtmlWeb();
htmlWeb.UseCookies = true;


HtmlDocument htmlDocument = htmlWeb.Load(url);


// after getting the document node
// you can do something like this
foreach (HtmlNode item in htmlDocument.DocumentNode.Descendants("input"))
{ 
 // item mathces your req
 // take the item.
}
</code></pre>

New to C# here, but I've used Java for years. I tried googling this and got a couple of answers that were not quite what I need. I'd like to grab the (X)HTML from a website and then use DOM (actually, CSS selectors are preferable, but whatever works) to grab a particular element. How exactly is this done in C#?

Grabbing content from a website in C#

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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这里是C#的新手，但我已经用了很多年了。我试着用谷歌搜索一下，得到了几个我不太需要的答案。我想从网站上抓取(X)HTML，然后使用DOM (实际上，CSS选择器更好，但也行得通)来抓取特定元素。在C#中到底是如何做到这一点的？

问在C#中从网站抓取内容
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