title: C# if-null-then-null expression
body: <p>Just for curiosity/convenience: C# provides two cool conditional expression features I know of:</p>
  
  <pre><code>string trimmed = (input == null) ? null : input.Trim();
  </code></pre>
  
  <p>and</p>
  
  <pre><code>string trimmed = (input ?? "").Trim();
  </code></pre>
  
  <p>I miss another such expression for a situation I face very often:</p>
  
  <p><strong>If the input reference is null, then the output should be null. Otherwise, the output should be the outcome of accessing a method or property of the input object.</strong></p>
  
  <p>I have done exactly that in my first example, but <code>(input == null) ? null : input.Trim()</code> is quite verbose and unreadable.</p>
  
  <p><strong>Is there another conditional expression for this case, or can I use the <code>??</code> operator elegantly?</strong></p>