Private Sub dataGridView1_UserDeletingRow(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.DataGridViewRowCancelEventArgs) _
    Handles dataGridView1.UserDeletingRow

    If e.Row.Index < Me.customers.Count Then

        ' If the user has deleted an existing row, remove the 
        ' corresponding Customer object from the data store.
        Me.customers.RemoveAt(e.Row.Index)

    End If

    If e.Row.Index = Me.rowInEdit Then

        ' If the user has deleted a newly created row, release
        ' the corresponding Customer object. 
        Me.rowInEdit = -1
        Me.customerInEdit = Nothing

    End If

End Sub

private void dataGridView1_UserDeletingRow(object sender,
    System.Windows.Forms.DataGridViewRowCancelEventArgs e)
{
    if (e.Row.Index < this.customers.Count)
    {
        // If the user has deleted an existing row, remove the 
        // corresponding Customer object from the data store.
        this.customers.RemoveAt(e.Row.Index);
    }

    if (e.Row.Index == this.rowInEdit)
    {
        // If the user has deleted a newly created row, release
        // the corresponding Customer object. 
        this.rowInEdit = -1;
        this.customerInEdit = null;
    }
}