title: Parse DateTime from int like 2012, 201201 or 20120101
body: <p>I have three types of input integer, representing different datetime.</p>
  
  <p>1) yyyy, e.g. 2012</p>
  
  <p>2) yyyyMM, e.g. 201201</p>
  
  <p>3) yyyyMMdd, e.g. 20120101</p>
  
  <p>I need to write a method to parse them to datetime.</p>
  
  <pre><code>public static DateTime ConvertToDateTime(int intDateTime)
  {
      // How to do this
  }
  </code></pre>