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+2  Q: 

Parsing XML from the National Weather Service SOAP Service in C# LINQ to XML

Hello folks, I'm a junior C# programmer that's trying to develop a library that will allow me to encapsulate the nasty details of parsing the XML returned from the NWS, and returning a collection representing the data.

My SOAP request would return an XML document in this form:

<?xml version="1.0" encoding="UTF-8"?>
<dwml version="1.0" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://www.nws.noaa.gov/forecasts/xml/DWMLgen/schema/DWML.xsd"&gt;
  <head>
    <product srsName="WGS 1984" concise-name="time-series" operational-mode="official">
      <title>NOAA's National Weather Service Forecast Data</title>
      <field>meteorological</field>
      <category>forecast</category>
      <creation-date refresh-frequency="PT1H">2009-02-04T20:01:00Z</creation-date>
    </product>
    <source>
      <more-information>http://www.nws.noaa.gov/forecasts/xml/&lt;/more-information&gt;
      <production-center>Meteorological Development Laboratory<sub-center>Product Generation Branch</sub-center></production-center>
      <disclaimer>http://www.nws.noaa.gov/disclaimer.html&lt;/disclaimer&gt;
      <credit>http://www.weather.gov/&lt;/credit&gt;
      <credit-logo>http://www.weather.gov/images/xml_logo.gif&lt;/credit-logo&gt;
      <feedback>http://www.weather.gov/feedback.php&lt;/feedback&gt;
    </source>
  </head>
  <data>
    <location>
      <location-key>point1</location-key>
      <point latitude="42.23" longitude="-83.27"/>
    </location>
    <moreWeatherInformation applicable-location="point1">http://forecast.weather.gov/MapClick.php?textField1=42.23&amp;amp;textField2=-83.27&lt;/moreWeatherInformation&gt;
    <time-layout time-coordinate="local" summarization="none">
      <layout-key>k-p24h-n7-1</layout-key>
      <start-valid-time>2009-02-04T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-04T19:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-05T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-05T19:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-06T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-06T19:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-07T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-07T19:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-08T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-08T19:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-09T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-09T19:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-10T07:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-10T19:00:00-05:00</end-valid-time>
    </time-layout>
    <time-layout time-coordinate="local" summarization="none">
      <layout-key>k-p24h-n6-2</layout-key>
      <start-valid-time>2009-02-04T19:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-05T08:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-05T19:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-06T08:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-06T19:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-07T08:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-07T19:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-08T08:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-08T19:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-09T08:00:00-05:00</end-valid-time>
      <start-valid-time>2009-02-09T19:00:00-05:00</start-valid-time>
      <end-valid-time>2009-02-10T08:00:00-05:00</end-valid-time>
    </time-layout>
    <parameters applicable-location="point1">
      <temperature type="maximum" units="Fahrenheit" time-layout="k-p24h-n7-1">
        <name>Daily Maximum Temperature</name>
        <value>15</value>
        <value>19</value>
        <value>33</value>
        <value>46</value>
        <value>41</value>
        <value>43</value>
        <value>44</value>
      </temperature>
      <temperature type="minimum" units="Fahrenheit" time-layout="k-p24h-n6-2">
        <name>Daily Minimum Temperature</name>
        <value>-2</value>
        <value>16</value>
        <value>29</value>
        <value>32</value>
        <value>27</value>
        <value>32</value>
      </temperature>
    </parameters>
  </data>
</dwml>

I'm trying to put the maximum and minimum temps that are inside this XML in separate collections of strings while ignoring the "name" elements using LINQ.

Edit: This is the code I use to get the XML from the Web Reference:

    WeatherNWS.ndfdXML client = new TestNWS.WeatherNWS.ndfdXML();

    string XMLZip = client.LatLonListZipCode("48180");

    XElement myElement = XElement.Parse(XMLZip);
    string[] myString = myElement.Value.Split(',');

    decimal lat = Convert.ToDecimal(myString[0]);
    decimal lon = Convert.ToDecimal(myString[1]);

    weatherParametersType parameters = new weatherParametersType();

    parameters.maxt = true;
    parameters.mint = true;

    string XML = client.NDFDgen(lat, lon, productType.timeseries, DateTime.Now, DateTime.Now.AddDays(7), parameters);
A: 

You'll probably need to parse the xml you get back with xpath to pull out the data you want. There's a brief example here.

Alternatively you could create a class structure that mirrors the xml structure and use the XmlSerializer to deserialize the xml into objects, but that's probably more trouble than it's worth in this case.

Kevin Tighe  2009-02-04 22:53:58
+2  A: 

This should be able to get the maximum temperatures for you, you would just have to change the where filter to get the minimums

 using System.Xml.Linq;
 \\...

 XDocument xmlDoc = XDocument.Load("YourXml.xml");
 var maximums = from tempvalue in xmlDoc.Descendants("temperature").Elements("value")
                           where tempvalue.Parent.Attribute("type").Value == "maximum"
                           select (string)tempvalue;

List<string> returnme = maximums.ToList<string>();
return returnme;

Hope this help.

Note: I'm a bit rusty with my Linq to Xml in C# so it may not be the most elegant solution.

Nathan W  2009-02-04 22:54:06
There's no Elements method inside of Descendants.
M4dRefluX  2009-02-05 01:24:22
make sure you have System.Xml.Linq namespace added. See my edit.
Nathan W  2009-02-05 02:03:47
It's added, it just shows up as a generic extension though.
M4dRefluX  2009-02-05 02:44:10
@M4dReflux whats the problem with that?
Nathan W  2009-02-05 03:26:57
Oh my mistake, I'm still a newbie in C#, I thought it was necessary to put a type in the angle brackets, but I tried it and it worked nicely. Thanks a lot!
M4dRefluX  2009-02-05 03:35:18
@M4dRefluX No problem, we are all newbies at some stage. Yeah the complier will infer the type, you gotta love it. :)
Nathan W  2009-02-05 03:51:05

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