title: How can convert a List to another List with explicit operator with out using extention method
body: <p>I add this operator to my class and works well when I pass a class of "A" it convert to class "B".</p>
  
  <pre><code>public static explicit operator B (A a)
  {
      //Convert A to B
  }
  </code></pre>
  
  <p>but when I want to convert a list of "A" to a List of "B" it doesn't work.
  and I try below code but it doesn't work too.</p>
  
  <pre><code>public static explicit operator List&lt;B&gt;(List&lt;A&gt; a)
     {
         //Convert List&lt;A&gt; to List&lt;B&gt;
     }
  </code></pre>
  
  <p>It throw compiler error "User-defined conversion must convert to or from the enclosing type"
  I don't want to use extention method to cast it</p>