DataGridView1.Columns("C").DefaultCellStyle.Format = "c"

Private Sub dataGridView1_EditingControlShowing(ByVal sender As Object, _       ByVal e As DataGridViewEditingControlShowingEventArgs) _       Handles DataGridView1.EditingControlShowing       Dim txtEdit As TextBox = e.Control       RemoveHandler txtEdit.KeyPress, AddressOf txtEdit_Keypress       AddHandler txtEdit.KeyPress, AddressOf txtEdit_Keypressend sub

Private Sub txtEdit_Keypress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
 If e.KeyChar = "-" Then
                Dim curCell As DataGridViewCell = DataGridView1.CurrentCell
                If curCell.ColumnIndex = 2 Then
                    curCell.Value = -CDec(curCell.Value)
                    DataGridView1.RefreshEdit()
                    e.Handled = True
                End If
            End If
end sub