Casting between two types derived from the (same) interface
<p>I have an interface and two types that derive from it.</p>

<p>However, I cannot do the following:</p>

<pre><code>B objectB = (B) objectA
</code></pre>

<p>Where B derives from Interface1 (I am making up the name of classes but the point still stands), and likewise for objectA (which is of type A). I get the following error message:</p>

<blockquote>
  <p>Cannot cast expression of type A to B. </p>
</blockquote>

<p>Both types are deriving from the interface, what am I missing?</p>
