private void TbPvpCImposto_TextChanged(object sender, TextChangedEventArgs e) { if (tbPvpCImposto.Text.Length != 0 && tbPvpCImposto.Text.Substring(tbPvpCImposto.Text.Length - 1, 1) != ",") { tbPvpSImposto.TextChanged -= this.TbPvpSImposto_TextChanged; if (TextBoxValidator((TextBox)sender) && cbImpostos.SelectedItem != null && tbPvpCImposto.Text.Length != 0) { double preco = double.Parse(tbPvpCImposto.Text); Imposto imposto = (Imposto)cbImpostos.SelectedItem; tbPvpSImposto.Text = string.Format("{0:#0.00}", Calculos.DecrementaImposto(preco, imposto.Taxa)); } tbPvpSImposto.TextChanged += this.TbPvpSImposto_TextChanged; } }