VB.NET Click a checkbox into Datagridview

I have a DatagridView with data directly from a recordset.

I had a new column before the others as a checkbox type with this code:

Dim chk As New DataGridViewCheckBoxColumn()
gridRicette.Columns.Add(chk)
chk.HeaderText = "Sel."
chk.Name = "chk"

And it appear. But when I click on the the checkbox, nothing happens.

Can you help me to solve it?

Thanks!