title: Write DataSet to XML file with proper child parent relationships
body: <pre><code>DataSet newdataSet = new DataSet();       
  DataSet dataSet = new DataSet();  
  dataSet.ReadXml(readXml);  
  newDataSet.Tables.Add(dataSet.Tables["A"].Copy());  
  newDataSet.Tables.Add(dataSet.Tables["B"].Copy());  
  newDataSet.Tables.Add(dataSet.Tables["C"].Copy());  
  </code></pre>
  
  <p>Now When i write it to a XMl file ,I want the following output:</p>
  
  <pre><code>&lt;A&gt; &lt;B&gt; &lt;C/&gt; &lt;B/&gt; &lt;B&gt; &lt;C/&gt; &lt;B/&gt; &lt;/A&gt;
  </code></pre>
  
  <p>I have also tried by adding relations among the table by :<code>A-&gt;B,B-&gt;C</code></p>
  
  <pre><code>newDataSet.Relations.Add(newDataSet.Tables["A"].Columns["A_Id"],newDataSet.Tables["B"].Columns["A_Id"]);   
  newDataSet.Relations.Add(newDataSet.Tables["B"].Columns["B_Id"],newDataSet.Tables["C"].Columns["B_Id"]);
  </code></pre>
  
  <p>But the output is still:</p>
  
  <pre><code>&lt;A/&gt; &lt;B/&gt; &lt;B/&gt; &lt;c/&gt; &lt;C/&gt; 
  </code></pre>