Option pricing with discrete dividends using the Binomial Tree model

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace BinomialTreeUI
{
    public partial class Form1 : Form
    {
        private int _exceptionCount=0;
        public Form1()
        {
            InitializeComponent();
        }

         void button1_Click(object sender, EventArgs e)
        {
            try
            {

            #region  GetFormInformation
                _exceptionCount=0;
                 double _stockPrice = 0.0;
                 double _strike = 0.0;
                 double _timeToExpiration = 0.0;
                 double _volatility = 0.0;
                 double _riskFreeRate = 0.0;

                 EPutCall _putCall = EPutCall.Call;
                 EnumStyle _style = EnumStyle.American;
                
                 int _steps = 100;

                 double _dividendYield = 0;
                 bool _isFuture = false;
                 double _dividend1 = 0;
                 double _dividend1Date = 0;

                 double _dividend2 = 0;
                 double _dividend2Date = 0;

                 double _dividend3 = 0;
                 double _dividend3Date = 0;

                 double _dividend4 = 0;
                 double _dividend4Date = 0;

                //validate information
                if(IsNotNullAndIsPositiveDouble(txtStockPrice.Text))
                    _stockPrice = Convert.ToDouble(txtStockPrice.Text);

                if(IsNotNullAndIsPositiveDouble(txtStrike.Text))
                    _strike = Convert.ToDouble(txtStrike.Text);

                if(IsNotNullAndIsPositiveDouble(txtTimeToExpiration.Text))
                    _timeToExpiration = Convert.ToDouble(txtTimeToExpiration.Text);

                if(IsNotNullAndIsPositiveDouble(txtVol.Text))
                    _volatility = Convert.ToDouble(txtVol.Text);

                if(IsNotNullAndIsPositiveDouble(txtRate.Text))
                    _riskFreeRate = Convert.ToDouble(txtRate.Text);

                if(IsNotNullAndIsPositiveDouble(txtYield.Text))
                    _dividendYield = Convert.ToDouble(txtYield.Text);

                
                if (dividend1.Text!=String.Empty && double.TryParse(dividend1.Text, out _dividend1))
                {
                    if(date1.Text!=String.Empty)
                        _dividend1Date = Convert.ToDouble(date1.Text);
                }
                if (dividend2.Text!=String.Empty && double.TryParse(dividend2.Text, out _dividend2))
                {
                    if(date2.Text!=String.Empty)
                        _dividend2Date = Convert.ToDouble(date2.Text);
                }
                if (dividend3.Text!=String.Empty && double.TryParse(dividend3.Text, out _dividend3))
                {
                    if(date3.Text!=String.Empty)
                        _dividend3Date = Convert.ToDouble(date3.Text);
                }
                if (dividend4.Text!=String.Empty && double.TryParse(dividend4.Text, out _dividend4))
                {
                    if(date4.Text!=String.Empty)
                        _dividend4Date = Convert.ToDouble(date4.Text);
                }


                if (txtSteps.Text != string.Empty && Int32.TryParse(txtSteps.Text,out _steps) && _steps > 0)
                {
                }
                else
                {
                    _steps = 100;
                }

                if(rdoCall.Checked)
                    _putCall = EPutCall.Call;
                else if (rdoPut.Checked)
                    _putCall = EPutCall.Put;

                if(chkAmerican.Checked)
                    _style = EnumStyle.American;
                else
                    _style = EnumStyle.European;

                if(chkFuture.Checked)
                    _isFuture = true;


            #endregion

               lblResult.Text=String.Empty;
                BinomialTree tree = new BinomialTree(_stockPrice,_strike, _timeToExpiration,
                    _volatility,_riskFreeRate,_putCall,_style,_steps,_dividendYield,_isFuture,
                    _dividend1,_dividend1Date,_dividend2,_dividend2Date,
                    _dividend3,_dividend3Date,_dividend4,_dividend4Date);

                //decimal presentValue = Convert.ToDecimal(tree.OptionValue());
                //System.Diagnostics.Debug.WriteLine(string.Format("{0},{1}", _steps.ToString(), presentValue.ToString()));
                lblResult.Text = tree.ComputeOptionValues().ToString();              
            }
            catch (FormatException)
            { 
                lblResult.Text = "An input was not in the correct format. Please check your input values";
            }
        }
        #region UtilityFunctions
        bool IsNotNull(string value)
        {
            if (value != null && value != String.Empty)
            { return true; }
            else
            {
                _exceptionCount++;
                return false;
            }
        }
        bool IsNotNullAndIsPositiveDouble(string value)
        {
            try
            {
                if (value != null && value != String.Empty && Convert.ToDouble(value) > 0)
                { return true; }
                else
                {
                    _exceptionCount++;
                    return false; 
                }
            }
            catch(FormatException)
            {
                lblResult.Text = "An input was not in the correct format";
                return false;
            }
        }
        #endregion 
    }
}