title: Allow only one checkbox selected in DataGridView
body: <p>I have a datagridview fill with data from database. The first column is a checkboxcolumn (data for this column retrieved from database is type BIT) and I want the user only check one. If the user select other one, the first one have to be unchecked.</p>
  
  <p>I have seen a lot of code and none works.</p>
  
  <p>What I could do?</p>
  
  <p>Is a Winforms C# app with SQL SERVER.</p>