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POLINQ to XML NullReferenceException AFTER returning the results?
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  1. POLINQ to XML NullReferenceException AFTER returning the results?
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    copied!<p>I'm quite new to .NET and even more so to LINQ, which I have just begun exploring for a small project I'm working on.</p> <p>I have a XML file generated from an application that contains a few values that I want to parse into a proprietary format and save in a file.</p> <p>I'm able to make one LINQ query work fine, returning values to my Console app. Then the second query runs, also returns the requested values, but <em>then</em> throws a NRE! Why doesn't it stop iterating over the resultset after the third value has been returned?</p> <p>First, heres an excerpt of the XML file:</p> <pre><code>&lt;analyse&gt; &lt;sample&gt;Leer 12&lt;/sample&gt; sample ID and number &lt;id&gt;Leer&lt;/id&gt; sample ID &lt;/analyse&gt; &lt;results&gt; &lt;element&gt; &lt;name&gt;c&lt;/name&gt; &lt;value&gt;0.000186156337031958&lt;/value&gt; &lt;/element&gt; &lt;element&gt; &lt;name&gt;co2&lt;/name&gt; &lt;value&gt;0.000682099902270885&lt;/value&gt; &lt;/element&gt; &lt;element&gt; &lt;name&gt;s&lt;/name&gt; &lt;value&gt;0.000121750914950204&lt;/value&gt; &lt;/element&gt; &lt;element&gt; &lt;name&gt;so3&lt;/name&gt; &lt;value&gt;0.000304028592755094&lt;/value&gt; &lt;/element&gt; &lt;/results&gt; </code></pre> <p>This is the first LINQ query:</p> <pre><code>XDocument uniSample = XDocument.Load(limsfile); var analyse = uniSample.Descendants("analyse").Select(el =&gt; new { Sample = el.Element("sample").Value, Id = el.Element("id").Value }); foreach (var el in analyse) { Console.WriteLine("Sample: " + el.Sample); Console.WriteLine("Sample ID: " + el.Id); } </code></pre> <p>This is the second LINQ query: (note how I had to rename the anonynous type Value because it seemed to conflict with something) </p> <pre><code>var results = uniSample.Descendants("element").Select(elements =&gt; new { Name = elements.Element("name").Value, Verdi = elements.Element("value").Value }); foreach (var el in results) { Console.WriteLine("Name: " + el.Name); Console.WriteLine("Value: " + el.Verdi); } </code></pre> <p>Now the output from the program looks like what you'd expect</p> <pre><code>Sample: Leer 12 Sample ID: Leer Name: c Value: 0.000186156337031958 Name: co2 Value: 0.000682099902270885 Name: s Value: 0.000121750914950204 Name: so3 Value: 0.000304028592755094 </code></pre> <p>...but then after the third iteration, the NRE is thrown, pointing at the latter LINQ query. Why isn't it exiting the foreach loop like it does the first time??</p> <p>Edit: Actually it's after the FOURTH iteration, sorry for the mixup! :) Thanks!</p>
 

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