title: Preventing a new row from appearing in a DataGridView before current row is filled in?
body: <p>I have a DataGridView in my WinForm application in C# 3.5.</p>
  
  <p><code>AllowUserToAddNewRow</code> property is set true.  When user types any text in DataGridView, another new row is automatically added to DataGridView.  I do not want this new row added until some checks are performed on the current row and all the necessary information has been filled in there.</p>
  
  <p>Example : I have a DataGridView with a blank row:
  <img src="https://i.stack.imgur.com/7bPnI.png" alt="DataGridView with one blank row"></p>
  
  <p>When I begin typing a new row is added, which is too soon:
  <img src="https://i.stack.imgur.com/xmOno.png" alt=""></p>
  
  <p>What I want is that the new row be added only after the user enters a Quantity:
  <img src="https://i.stack.imgur.com/FnlyU.png" alt=""></p>