title: How to sort a DataGridView column that is has a DateTime Value, but is displayed as a String?
body: <p>i have in my program a datagriview,i want to order columns by data,i use:</p>
  
  <pre><code>dataGridView1.Columns["Date"].ValueType = typeof(DateTime);
  </code></pre>
  
  <p>but when i click on Date column,it's didn't sort correctly.</p>
  
  <p>my date format is: 23-12-1997</p>
  
  <p>is incorrect write format of date?</p>