title: LINQ Select certain cell in DataGridView depending on other cell in row
body: <p>I am brand spanking new to LINQ and am trying to use it in my current hobby project. I have a <code>datagridview</code> where the first cell of each row is a <code>datagridviewcheckbox</code>, and the 4th cell is a string.</p>
  
  <p>If the checkbox is checked, I need to add the 4th cell's value to a list.</p>
  
  <p>At first I tried:</p>
  
  <pre><code>var selectedID = from c in multiContactLookup.SelectedCells.Cast&lt;DataGridViewCell&gt;() 
                                select multiContactLookup.Rows[c.RowIndex].Cells[4].Value;
  </code></pre>
  
  <p>That didn't work because the checked cells are programatically unselected so <code>c</code> is never a value.</p>
  
  <p>Then I tried:</p>
  
  <pre><code>var sel2 = from r in multiContactLookup.Rows.Cast&lt;DataGridViewRow&gt;()
                         where r.Cells[0].Value is true select r.Cells[4].Value;
  </code></pre>
  
  <p>but somehow my syntax is wrong.</p>
  
  <p>Using LINQ, how can I select the rows where the first cell is checked then select the value of the first cell?  Do I have to split this into two collections?</p>
  
  <p>Thank you!</p>