title: One-line if-else in C#
body: <p>In C#, is there a one-line implementation of the following simple piece of logic ?</p>
  
  <pre><code>if (a != null) 
  {
      b = a ;
  }
  else
  {
      // do something else;
  }
  </code></pre>
  
  <p>Notice that in the <code>else</code> I do not want to assign a different value to the variable b.</p>