MortgageCalculator.cs

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

namespace MortgageCalculator
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void btnCalculate_Click(object sender, EventArgs e)
{
CalculateTheMortgage();
}

private void CalculateTheMortgage()
{
//  (Loan Value) *  (1 + r/12) ^ p =  (12x / r)  *  ((1 + r/12)^p – 1)
// payment = (((Loan Value) *  (1 + r/12) ^ p) * r)/ (12 * ((1 + r/12)^p – 1)));
double loanAmount = (double)txtLoanAmount.CurrentValue; // price of total mortgage before down payment
double taxesPerYear = (double)txtPropertyTax.CurrentValue; // this will divided by 12 and added to the monthly payment
double downPayment = (double)txtDownPayment.CurrentValue; // down payment will be subtracted from the loan
double interestRate = (double)udInterest.Value / 100;  // calculate interest from 100%
double termOfLoan = (double)(udTerm.Value * 12); // monthly term
double propertyTax = (double)txtPropertyTax.CurrentValue;
double insurance = (double)txtInsurance.CurrentValue;

double payment =  (loanAmount – downPayment) * (Math.Pow((1 + interestRate/12), termOfLoan) * interestRate)/(12 * (Math.Pow((1+interestRate/12), termOfLoan) – 1));

// add on a monthly property tax
payment = payment + (propertyTax + insurance) / 12;

txtPayment.CurrentValue = (int)payment;
}

}
}