title: Best way to handle a NULL
body: <p>At the top of my functions I'm trying the best way to handle a null coming into my procedures in C#. Which is the best way for checking and handling the null and why? I've added the complete code of what I'm using right now and Resharper is telling me to use Option #1. Normally I do what it says as I understand why it makes it more efficient. This time though I'm not sure so I must ask.</p>
  
  <pre><code>Option #1
  if (sender == null) return;
  
  // Code goes here
  
  or
  
  Option #2
  if (sender != null)
  { 
       // Code goes here
  }
  
  Complete Code
          private void EmployeeMouseHoverToolTip(object sender, EventArgs e)
          {
              if (sender != null)
              {
                  var sUserIdentifier = ((C1TextBox)sender).Text;
                  var userIdentifier = Guid.Empty;
                  if (Utilities.IsGuid(sUserIdentifier))
                  {
                      userIdentifier = new Guid(sUserIdentifier);
                  }
  
                  var toolTipText = Utilities.UserIdentifierToName(userIdentifier);
                  c1SuperTooltip.SetToolTip(sender as C1TextBox, toolTipText);
              }
          }
  </code></pre>