title: Extension Method ConvertAll
body: <p>What is the proper use of ConverAll ? Will it convert one type to another type?</p>
  
  <p>like </p>
  
  <pre><code>List&lt;int&gt; intList = new List&lt;int&gt;();
  intList.Add(10);
  intList.Add(20);
  intList.Add(30);
  intList.Add(33);
  
  var query= intList.ConvertAll(x=&gt;(double)x);
  </code></pre>
  
  <p>for this i can use cast or OfType&lt;>.</p>