title: deleting rows which contain null values on specified columns
body: <p>I have a <code>datagridview</code> on my <code>winform</code> which returns a search result from my database. After the search is returned, I would like to delete null rows from an specified column.
  Here's an example:</p>
  
  <p><img src="https://i.stack.imgur.com/fVoOB.png" alt="enter image description here"></p>
  
  <p>let's say that I want to delete the rows which have null value on the type <code>#2</code> column.</p>
  
  <p>I am totally stuck. How should I do this?</p>