private void qtdPorcao_TextChanged(object sender, EventArgs e)
        {
            TextBox txt = (TextBox)sender;

            FormatHelper.FormataMoeda(ref txt);
        }
        private void txtPrecoVenda_TextChanged(object sender, EventArgs e)
        {
            TextBox txt = (TextBox)sender;

            FormatHelper.FormataMoeda(ref txt);
        }