Mortgage Calculator (C#)

// calculate your monthly mortgage payments
// a C# Windows GUI with a Form, Labels, TextBoxes, and a Button
// compiled with the neat SnippetCompiler.exe (which uses csc.exe)
// from: http://www.sliver.com/dotnet/SnippetCompiler/
// C# and .NET Framework V2.0     vegaseat    03apr2007

using System;
using System.Windows.Forms;

namespace MortgagePayments
{
  public class Form1 : System.Windows.Forms.Form
  {
    private System.Windows.Forms.Label label1;
    private System.Windows.Forms.Label label2;
    private System.Windows.Forms.Label label3;
    private System.Windows.Forms.Label label4;
    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.TextBox textBox1;
    private System.Windows.Forms.TextBox textBox2;
    private System.Windows.Forms.TextBox textBox3;
    private System.ComponentModel.Container components = null;

    public Form1()
    {
      InitializeComponent();
    }

    protected override void Dispose( bool disposing )
    {
      if ( disposing )
      {
        if (components != null) 
        {
          components.Dispose();
        }
      }
      base.Dispose( disposing );
    }

    #region Windows Form Designer generated code
    private void InitializeComponent()
    {
      this.label1 = new System.Windows.Forms.Label();
      this.label2 = new System.Windows.Forms.Label();
      this.label3 = new System.Windows.Forms.Label();
      this.label4 = new System.Windows.Forms.Label();
      this.button1 = new System.Windows.Forms.Button();
      this.textBox1 = new System.Windows.Forms.TextBox();
      this.textBox2 = new System.Windows.Forms.TextBox();
      this.textBox3 = new System.Windows.Forms.TextBox();
      this.SuspendLayout();
      // 
      // label1
      // 
      this.label1.BackColor = System.Drawing.Color.PeachPuff;
      this.label1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
      this.label1.Location = new System.Drawing.Point(8, 8);
      this.label1.Name = "label1";
      this.label1.Size = new System.Drawing.Size(128, 23);
      this.label1.TabIndex = 0;
      this.label1.Text = "Enter total loan ";
      // 
      // label2
      // 
      this.label2.BackColor = System.Drawing.Color.PeachPuff;
      this.label2.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
      this.label2.Location = new System.Drawing.Point(8, 40);
      this.label2.Name = "label2";
      this.label2.Size = new System.Drawing.Size(128, 23);
      this.label2.TabIndex = 1;
      this.label2.Text = "Enter interest (%) ";
      // 
      // label3
      // 
      this.label3.BackColor = System.Drawing.Color.PeachPuff;
      this.label3.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
      this.label3.Location = new System.Drawing.Point(8, 72);
      this.label3.Name = "label3";
      this.label3.Size = new System.Drawing.Size(128, 23);
      this.label3.TabIndex = 2;
      this.label3.Text = "Enter years to pay ";
      // 
      // label4
      // 
      this.label4.BackColor = System.Drawing.Color.MistyRose;
      this.label4.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
      this.label4.Font = new System.Drawing.Font("Courier New", 7.8F, 
        System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, 
        ((System.Byte)(0)));
      this.label4.Location = new System.Drawing.Point(8, 152);
      this.label4.Name = "label4";
      this.label4.Size = new System.Drawing.Size(272, 96);
      this.label4.TabIndex = 3;
      this.label4.Text = "Change the values to your needs";
      // 
      // button1
      // 
      this.button1.BackColor = System.Drawing.Color.Khaki;
      this.button1.Location = new System.Drawing.Point(8, 112);
      this.button1.Name = "button1";
      this.button1.Size = new System.Drawing.Size(240, 23);
      this.button1.TabIndex = 4;
      this.button1.Text = "Perform Mortgage Calcuations";
      this.button1.Click += new System.EventHandler(this.button1_Click);
      // 
      // textBox1
      // 
      this.textBox1.Location = new System.Drawing.Point(152, 8);
      this.textBox1.Name = "textBox1";
      this.textBox1.TabIndex = 5;
      this.textBox1.Text = "100000";
      //
      // textBox2
      // 
      this.textBox2.Location = new System.Drawing.Point(152, 40);
      this.textBox2.Name = "textBox2";
      this.textBox2.TabIndex = 6;
      this.textBox2.Text = "6.5";
      // 
      // textBox3
      // 
      this.textBox3.Location = new System.Drawing.Point(152, 72);
      this.textBox3.Name = "textBox3";
      this.textBox3.TabIndex = 7;
      this.textBox3.Text = "30";
      // 
      // Form1
      // 
      this.AutoScaleBaseSize = new System.Drawing.Size(6, 15);
      this.BackColor = System.Drawing.Color.DarkGreen;
      this.ClientSize = new System.Drawing.Size(292, 260);
      this.Controls.Add(this.textBox3);
      this.Controls.Add(this.textBox2);
      this.Controls.Add(this.textBox1);
      this.Controls.Add(this.button1);
      this.Controls.Add(this.label4);
      this.Controls.Add(this.label3);
      this.Controls.Add(this.label2);
      this.Controls.Add(this.label1);
      this.Name = "Form1";
      this.Text = "Mortgage Calculator";
      this.ResumeLayout(false);
    }
    #endregion

    static void Main() 
    {
      Application.Run(new Form1());
    }

    private void button1_Click(object sender, System.EventArgs e)
    {
      double principal;     // total mortgage loan
      double interestPerc;  // percent annual interest
      double interestRate;  // monthly interest rate
      double years;         // years to pay
      double paymentNum;    // number of months to pay
      double paymentVal;    // value of monthly payment
      String fstr;

      this.label4.Text = "";
      principal = double.Parse(this.textBox1.Text);
      interestPerc = double.Parse(this.textBox2.Text);
      interestRate = interestPerc/(100 * 12);
      years = double.Parse(this.textBox3.Text);
      paymentNum = years * 12;
      
      paymentVal = principal * (interestRate/(1-Math.Pow((1+interestRate), (-paymentNum))));

      fstr = String.Format("Principal Loan: {0:C}\n", principal);
      this.label4.Text += fstr;
      this.label4.Text += "Interest (%)  : " + interestPerc + '\n';
      this.label4.Text += "Years to pay  : " + years + '\n';
      this.label4.Text += "Months to pay : " + paymentNum + '\n';
      fstr = String.Format("Monthly pay   : {0:C}\n", paymentVal);
      this.label4.Text += fstr;
      fstr = String.Format("Total pay     : {0:C}\n", paymentVal*paymentNum);
      this.label4.Text += fstr;
    }
  }
}