C# Convert interfaces
<p>Cast a class to an interface is the same as convert a Class to another Class in C#?Does box or unboxing occurs in this process?</p>

<pre><code>interface Area
{
   string TxtArea
   {
     get;
     set;
   }
}
</code></pre>

<p>Convert to it interface:</p>

<pre><code>public void Test()

    {
       ExternArea extArea = new ExternArea();
       if(extArea is Area)
       {
         ((Area)extArea).TxtArea = "voila";
       }
    }
</code></pre>
