I have a DataGridView in my WinForm application in C# 3.5.
AllowUserToAddNewRow 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.
Example : I have a DataGridView with a blank row:

When I begin typing a new row is added, which is too soon:

What I want is that the new row be added only after the user enters a Quantity:
