XML Node is null in c#

Question

Alright so I'm trying to get information from Yahoo finance using their YQL. The below code is what I'm using for that. I have tested the xml location string in a browser which does return xml code. I'm trying to read that code, parse it and MessageBox the node I'm looking for. The error is that the string text is null, I'm presuming this is because node is null, which is probably because doc is null. Why is doc null?

XmlDocument doc = new XmlDocument();
doc.Load("https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.stocks%20where%20symbol%3D%22" + txt_Symbol.Text + "%22&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys");
XmlNode node = doc.DocumentElement.SelectSingleNode("/results/stock/FullTimeEmployees");
string text = node.InnerText;

Sample Response From Yahoo YQL:

<query xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" yahoo:count="1" yahoo:created="2014-06-03T21:06:06Z" yahoo:lang="en-US">
<diagnostics>
<url execution-start-time="0" execution-stop-time="1" execution-time="1">
<![CDATA[
http://www.datatables.org/yahoo/finance/yahoo.finance.stocks.xml
]]>
</url>
<publiclyCallable>true</publiclyCallable>
<cache execution-start-time="4" execution-stop-time="4" execution-time="0" method="GET" type="MEMCACHED">
<![CDATA[ bcd022d1d39e092a7a1390d6f5cf574a ]]>
</cache>
<cache execution-start-time="4" execution-stop-time="5" execution-time="1" method="GET" type="MEMCACHED">
<![CDATA[ 32c5f8788e8bc68ba5e635ae25257e23 ]]>
</cache>
<cache execution-start-time="5" execution-stop-time="6" execution-time="1" method="GET" type="MEMCACHED">
<![CDATA[ 8c548d6a60dd1f067626b9ecdf556eb3 ]]>
</cache>
<url execution-start-time="5" execution-stop-time="288" execution-time="283">
<![CDATA[ http://finance.yahoo.com/q?s=ibm ]]>
</url>
<url execution-start-time="5" execution-stop-time="288" execution-time="283">
<![CDATA[ http://finance.yahoo.com/q?s=ibm ]]>
</url>
<query execution-start-time="5" execution-stop-time="294" execution-time="289" params="{url=[http://finance.yahoo.com/q?s=ibm]}">
<![CDATA[
select * from html where url=@url and xpath='//div[@id="yfi_investing_head"]/h1 | //div[@class="yfi_quote_summary"]/div[1]'
]]>
</query>
<url execution-start-time="5" execution-stop-time="430" execution-time="425">
<![CDATA[ http://finance.yahoo.com/q/pr?s=ibm ]]>
</url>
<url execution-start-time="5" execution-stop-time="430" execution-time="425">
<![CDATA[ http://finance.yahoo.com/q/pr?s=ibm ]]>
</url>
<url execution-start-time="7" execution-stop-time="455" execution-time="448">
<![CDATA[ http://finance.yahoo.com/q/hp?s=ibm ]]>
</url>
<query execution-start-time="4" execution-stop-time="434" execution-time="430" params="{url=[http://finance.yahoo.com/q/pr?s=ibm]}">
<![CDATA[
select * from html where url=@url and xpath='//table[@class="yfnc_datamodoutline1"]/tr/td/table/tr' limit 4
]]>
</query>
<url execution-start-time="7" execution-stop-time="455" execution-time="448">
<![CDATA[ http://finance.yahoo.com/q/hp?s=ibm ]]>
</url>
<query execution-start-time="6" execution-stop-time="461" execution-time="455" params="{url=[http://finance.yahoo.com/q/hp?s=ibm]}">
<![CDATA[
select * from html where url=@url and xpath='//option[@selected="selected"] | //input[@maxlength="2"] | //input[@maxlength="4"]'
]]>
</query>
<javascript execution-start-time="3" execution-stop-time="462" execution-time="459" instructions-used="46403" table-name="yahoo.finance.stocks"/>
<user-time>464</user-time>
<service-time>2251</service-time>
<build-version>0.2.2525</build-version>
</diagnostics>
<results>
<stock symbol="ibm">
<CompanyName/>
<start>1962-01-02</start>
<end>2014-06-03</end>
<Sector>Technology</Sector>
<Industry>Information Technology Services</Industry>
<FullTimeEmployees>431212</FullTimeEmployees>
</stock>
</results>
</query>
<!--  total: 464  -->
<!--  engine4.yql.bf1.yahoo.com  -->

Please make sure to show small piece of XML related to your post. There are way too many ways to get XPath to return "no nodes found" - case sensitivity, namespaces, wrong node... At least link to documentation. — Alexei Levenkov, Jun 02 '14 at 19:12
This question "lacks sufficient information to diagnose the problem"? There was enough there for me to diagnose the problem. — Luke Woodward, Jun 03 '14 at 19:28
I have edited the question to provide a sample output of what yahoo would return. — Kyle, Jun 03 '14 at 21:07

score 1 · Accepted Answer · answered Jun 02 '14 at 18:59

doc is not null. node is null, however, and this is because your XPath expression is wrong.

The name of the root element in the XML document you fetch is query, but your XPath expression /results/stock/FullTimeEmployees only matches if the root element has name results. As there are no matching nodes, SelectSingleNode returns null.

Try changing your XPath to either

/query/results/stock/FullTimeEmployees

or perhaps

//results/stock/FullTimeEmployees

(//results matches any element with name results at any depth in the document.)

XML Node is null in c#

1 Answers1