title: correct way to check string array is not null
body: <p>I have a string array and it always gives string array length > 0. what is the correct way to check that the string array is not null. </p>
  
  <pre><code>string[] mystr = new string[0];
  ...
  ...
  if (..) {
      mystr = string[] oldstrArray.Clone();
      }
  ...
  ...
  
  if (mystr[0].Length != 0) {
  //Always enters this loop even if mystr is not assigned in the above if condition
  }
  </code></pre>