private void DescuentoTxt_Leave(object sender, EventArgs e)
 {
     if (!PrincipalFrm.ValidarNumero(DescuentoTxt.Text))
     {
         DescuentoTxt.Focus();
         DescuentoTxt.BackColor = System.Drawing.Color.IndianRed;
         this._val = false;
     }
     else
     {
         DescuentoTxt.BackColor = System.Drawing.Color.White;
         this._val = true;
     }
 }
        private void DescuentoTxt_TextChanged(object sender, EventArgs e)
        {
            if (!(this.PrecioFinalLbl.Text != "") || !this.flagProduct)
            {
                return;
            }
            double num1 = Convert.ToDouble(this.PrecioLbl.Text.Substring(1, this.PrecioLbl.Text.Length - 2));

            this.DescuentoTxt.Text.IndexOf('%');
            if (this.DescuentoTxt.Text.IndexOf('%') == -1 && this.DescuentoTxt.Text != "")
            {
                double num2 = Convert.ToDouble(this.DescuentoTxt.Text);
                double num3 = num1 - num2;
                PrecioFinalLbl.Text = "= $" + num3.ToString("n2");
            }
            else if (this.DescuentoTxt.Text.IndexOf('%') > -1 && this.DescuentoTxt.Text != "")
            {
                int num2 = (int)this.DescuentoTxt.Text.Last <char>();

                double num3 = 0;

                try { num3 = Convert.ToDouble(this.DescuentoTxt.Text.Substring(0, this.DescuentoTxt.Text.Length - 1)); }
                catch (FormatException)
                {
                    DescuentoTxt.Text = "0%";
                    DescuentoTxt.SelectAll();
                    num3 = Convert.ToDouble(this.DescuentoTxt.Text.Substring(0, this.DescuentoTxt.Text.Length - 1));
                }
                double num4 = num1 / 100.0 * num3;
                this.PrecioFinalLbl.Text = "= $" + (num1 - num4).ToString("n2");
            }
            else
            {
                if (!(this.DescuentoTxt.Text == ""))
                {
                    return;
                }
                this.PrecioFinalLbl.Text = "= $" + num1.ToString("n2");
            }
        }