title: Ambiguous extension method
body: <p>I am making the following call to an extension method:</p>
  
  <pre><code>database.ExecuteScalar(command).NoNull&lt;string&gt;(string.Empty);
  </code></pre>
  
  <p>I get an error that the extension method is ambiguous .</p>
  
  <p>I have two dlls with the same code that implement <code>NoNull(string str)</code> under different  namespaces.</p>
  
  <p>How can I <strong>explicitly</strong> refer to one namespace?</p>
  
  <p>How would I have it done if it was the same namespace?</p>
  
  <p><strong>Update: I cannot rewrite the 3rd party dlls.</strong></p>