title: How to make format mask in DataGridView cell?
body: <p><strong>I need to make a format/mask in a cell that prevents the user from entering data that isn't relevant.</strong></p>
  
  <p>The column cell contains date values like <code>"MM/YYYY"</code> without a day value.</p>
  
  <p>I tried the following to make this definition but without success:</p>
  
  <pre><code>dataGridView1.Columns[0].DefaultCellStyle.Format = "##/####" // || dd/yyyy
  </code></pre>
  
  <p>Also, I tried to go to the properties of <code>DataGridView</code> and define <code>Format</code> from there.</p>