title: Casting object to an interface return null
body: <p>I have an object from a class which returns an interface. but when I cast the object to that interface it returns null. what is the problem?</p>
  
  <pre><code>public partial class CompanyConfigurations : SgConfigurationControl, `IWizardControl`
  
  CompanyConfigurations c
  c as IWizardControl
  </code></pre>