title: Difference between Convert.ToString(str) and str?.ToString() ?? ""
body: <p>Is there any difference between these two approaches?</p>
  
  <pre><code>static void Main(string[] args)
  {
      object str = null;
  
      string test1 = str?.ToString() ?? "";
  
      string test2 = Convert.ToString(str);
  }
  </code></pre>
  
  <p>Edit 1:</p>
  
  <p>As @Fabio pointed out, we have a third possible approach:</p>
  
  <pre><code>string test3 = $"{str}";
  </code></pre>