title: Calling Console.WriteLine(ex.Message) to prevent warning message
body: <p>We usually catch exception in the upper level of a code like the GUI (forms).</p>
  
  <p>But I usually have this kind of code</p>
  
  <pre><code>try
  {
  }
  catch(Exception ex)
  {
    Console.WriteLine(ex.Message);
    MessageBox.Show("Application has encountered error....");
  }
  </code></pre>
  
  <p>I could just catch(Exception) without the identifier because I do not need the message on runtime, but for the debugging build, it sure is convenient to break at the catch statement. So I usually write a Console.WriteLine to prevent a lot of warning of unused ex variable. I have a lot of case of Console.WriteLine(ex.Message) in my code. Does this cost performance decrease?</p>
  
  <p>Note: Changed title from "Does Console.WriteLine(ex.Message) have performance cost?" to "Calling Console.WriteLine(ex.Message) to prevent warning message"</p>