title: What does the question mark in member access mean in C#?
body: <p>Can someone please explain to me what does the question mark in the member access in the following code means?</p>
  
  <p>Is it part of standard C#? I get parse errors when trying to compile this file in Xamarin Studio.</p>
  
  <pre><code>this.AnalyzerLoadFailed?.Invoke(this, new AnalyzerLoadFailureEventArgs(AnalyzerLoadFailureEventArgs.FailureErrorCode.NoAnalyzers, null, null));
  </code></pre>
  
  <p><a href="https://github.com/mono/roslyn/blob/master/Src/Compilers/Core/Desktop/AnalyzerFileReference.cs" rel="noreferrer">AnalyzerFileReference.cs</a> line 195</p>