title: How can an object not be compared to null?
body: <p>I have an 'optional' parameter on a method that is a KeyValuePair.  I wanted an overload that passes null to the core method for this parameter, but in the core method, when I want to check if the KeyValuePair is null, I get the following error:</p>
  
  <pre><code>Operator '!=' cannot be applied to operands of type System.Collections.Generic.KeyValuePair&lt;string,object&gt;' and '&lt;null&gt;. 
  </code></pre>
  
  <p>How can I not be allowed to check if an object is null?</p>