title: Append Serialized Object Into XML in C#
body: <p>I have a XML structer like that</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;Product&gt;
    &lt;ProductName&gt;da&lt;/ProductName&gt;
    &lt;PluginPath&gt;&lt;/PluginPath&gt;
    &lt;Instances&gt;&lt;/Instances&gt;
  &lt;/Product&gt;
  </code></pre>
  
  <p>and i serialize my object to string. </p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;Instance xmlns:xsi="http://bla bla" xmlns:xsd="bla bla" UniqueId="d4820029b7d7"&gt;
  &lt;InstanceName&gt;Instance MyTestPluginForm&lt;/InstanceName&gt;
  &lt;Description&gt;Test Plugin IW&lt;/Description&gt;
  &lt;AddedDate&gt;2016-10-19T11:05:10.7443404+02:00&lt;/AddedDate&gt;
  &lt;LogSettings&gt;
  &lt;LoggingLevel&gt;None&lt;/LoggingLevel&gt;
  &lt;LogFilePath /&gt;&lt;MaximumSize&gt;100&lt;/MaximumSize
  &lt;ClearAfterDays&gt;7&lt;/ClearAfterDays&gt;
  &lt;IsSaveActiviesToEventLog&gt;false&lt;/IsSaveActiviesToEventLog&gt;
  &lt;/LogSettings&gt;
  &lt;ProductSpecific/&gt;
  &lt;/Instance&gt;
  </code></pre>
  
  <p>So I want to append the second one in the Instances node in the first xml. But as you see both has xml definition on the top and after serializazion i got xmlns:xsi and xmlns:xsd attributes. </p>
  
  <p>How to solve this problem?</p>
  
  <p>PS: I do not want to create XML elements. Because my xml schema is dynamic. It has to be done with serialization. (I already checked <a href="https://stackoverflow.com/questions/6703782/serialize-xml-and-append-new-elements-to-xml-file">this</a> sample)</p>