Loan Amortization Application in WPF using VC++

#include "PaymentWindow.h"

PaymentWindow::PaymentWindow()
{
	totalpayments = 0;
	payment = 0.0;

	Title = L"Amortization";
	Height = 480;
	Width = 640;
	WindowStyle = Windows::WindowStyle::ToolWindow;
	ResizeMode = Windows::ResizeMode::NoResize;
	WindowStartupLocation = Windows::WindowStartupLocation::CenterOwner;

	Grid^ grid = gcnew Grid();
	grid->Background::set(Media::Brushes::LightSalmon);

	// Create Rows in grid layout
	Windows::Controls::RowDefinition^ row1 = gcnew Windows::Controls::RowDefinition();
	Windows::Controls::RowDefinition^ row2 = gcnew Windows::Controls::RowDefinition();
	Windows::Controls::RowDefinition^ row3 = gcnew Windows::Controls::RowDefinition();
	Windows::Controls::RowDefinition^ row4 = gcnew Windows::Controls::RowDefinition();
	Windows::Controls::RowDefinition^ row5 = gcnew Windows::Controls::RowDefinition();

	// Create Columns in grid layout
	Windows::Controls::ColumnDefinition^ col1 = gcnew Windows::Controls::ColumnDefinition();
	Windows::Controls::ColumnDefinition^ col2 = gcnew Windows::Controls::ColumnDefinition();

	row1->Height = Windows::GridLength(45);
	row2->Height = Windows::GridLength(45);;
	row3->Height = Windows::GridLength(45);;
	row5->Height = Windows::GridLength(45);;

	// Add all the rows into grid
	grid->RowDefinitions->Add(row1);
	grid->RowDefinitions->Add(row2);
	grid->RowDefinitions->Add(row3);
	grid->RowDefinitions->Add(row4);
	grid->RowDefinitions->Add(row5);

	// Add all the columns into grid
	grid->ColumnDefinitions->Add(col1);
	grid->ColumnDefinitions->Add(col2);

	// Title of the Window
	lblTitle = gcnew Label();
	lblTitle->Content = L"Amortization Schedule";
	lblTitle->VerticalAlignment = Windows::VerticalAlignment::Center;
	lblTitle->HorizontalAlignment = Windows::HorizontalAlignment::Center;
	lblTitle->FontSize = 16;
	grid->SetRow(lblTitle, 0);
	grid->SetColumn(lblTitle, 0);
	grid->SetColumnSpan(lblTitle, 2);

	// Label of Monthly payment
	lblMonthlyPayment = gcnew Label();
	lblMonthlyPayment->Margin = Thickness(5);
	lblMonthlyPayment->Content = L"Monthly Payment";
	lblMonthlyPayment->VerticalAlignment = Windows::VerticalAlignment::Center;
	grid->SetRow(lblMonthlyPayment, 1);
	grid->SetColumn(lblMonthlyPayment, 0);

	// Text Box of Monthly Payment
	txtMonthlyPayment = gcnew TextBox();
	txtMonthlyPayment->Margin = Thickness(5);
	txtMonthlyPayment->VerticalAlignment = Windows::VerticalAlignment::Center;
	grid->SetRow(txtMonthlyPayment, 1);
	grid->SetColumn(txtMonthlyPayment, 1);

	// Label of Total
	lblTotal = gcnew Label();
	lblTotal->Margin = Thickness(5);
	lblTotal->Content = L"Total Amount Paid";
	lblTotal->VerticalAlignment = Windows::VerticalAlignment::Center;
	grid->SetRow(lblTotal, 2);
	grid->SetColumn(lblTotal, 0);

	// Text Box of Total
	txtTotal = gcnew TextBox();
	txtTotal->Margin = Thickness(5);
	txtTotal->VerticalAlignment = Windows::VerticalAlignment::Center;
	grid->SetRow(txtTotal, 2);
	grid->SetColumn(txtTotal, 1);

	// List View
	grdView = gcnew GridView();
	grdView->ColumnHeaderToolTip = L"Amortization Schedule";

	// Create payment no columnd and bind it
	GridViewColumn^ paymentNo = gcnew GridViewColumn();
	paymentNo->DisplayMemberBinding = gcnew Data::Binding("PaymentNo");
	paymentNo->Header = L"Payment No";
	paymentNo->Width = 100;
	grdView->Columns->Add(paymentNo);

	// Create Payment column and bind it
	GridViewColumn^ payment = gcnew GridViewColumn();
	payment->DisplayMemberBinding = gcnew Data::Binding("Payment");
	payment->Header = L"Payment";
	payment->Width = 100;
	grdView->Columns->Add(payment);

	// Create Principle column and bind it
	GridViewColumn^ principle = gcnew GridViewColumn();
	principle->DisplayMemberBinding = gcnew Data::Binding("Principle");
	principle->Header = L"Principle";
	principle->Width = 100;
	grdView->Columns->Add(principle);

	// Create Interest column and bind it
	GridViewColumn^ interest = gcnew GridViewColumn();
	interest->DisplayMemberBinding = gcnew Data::Binding("Interest");
	interest->Header = L"Interest";
	interest->Width = 100;
	grdView->Columns->Add(interest);

	// Create Balance column and bind it
	GridViewColumn^ balance = gcnew GridViewColumn();
	balance->DisplayMemberBinding = gcnew Data::Binding("Balance");
	balance->Header = L"Balance";
	balance->Width = 100;
	grdView->Columns->Add(balance);

	lstView = gcnew ListView();
	lstView->Margin = Thickness(5);
	lstView->View = grdView;

	//lstView->View::set(Windows::Controls::ViewBase::ViewBase);
	grid->SetRow(lstView, 3);
	grid->SetColumn(lstView, 0);
	grid->SetColumnSpan(lstView, 2);

	// Button to exit
	btnExit = gcnew Button();
	btnExit->Content = "Exit";
	btnExit->Width = 120;
	btnExit->Margin = Thickness(10);
	btnExit->Click += gcnew RoutedEventHandler(this, &PaymentWindow::OnBtnExit);
	grid->SetRow(btnExit, 4);
	grid->SetColumn(btnExit, 0);
	grid->SetColumnSpan(btnExit, 2);

	// add all the controls into grid
	grid->Children->Add(lblTitle);
	grid->Children->Add(lblMonthlyPayment);
	grid->Children->Add(txtMonthlyPayment);
	grid->Children->Add(lblTotal);
	grid->Children->Add(txtTotal);
	grid->Children->Add(lstView);
	grid->Children->Add(btnExit);

	Content = grid;

	this->Loaded += gcnew RoutedEventHandler(this, &PaymentWindow::OnLoad);	
}

void PaymentWindow::OnLoad(Object^ sender, RoutedEventArgs^ e)
{
	DisplayAmortization();
}

void PaymentWindow::OnBtnExit(Object^ sender, RoutedEventArgs^ e)
{
	Close();
}

void PaymentWindow::DisplayAmortization()
{
	CalculatePayment();

	// total amount paid
	double totalAmount = payment * totalpayments;

	txtTotal->Text = Convert::ToString(totalAmount);
	txtMonthlyPayment->Text = Convert::ToString(payment);

}

// Calculate the complete amortization schedule and fill the list control
void PaymentWindow::CalculatePayment()
{
	Title = L"Amortizatin Schedule for " + Convert::ToString(totalpayments) + " Payments";

	// calculate interest term
	double interestTerm = Math::Pow((1 + interestRate), totalpayments);

	// calculate payment
	payment = (principle * interestRate) / (1 - (1 / interestTerm));

	for (int iIndex = 1; iIndex <= totalpayments; ++iIndex)
	{
		PaymentInfo^ paymentInfo = gcnew PaymentInfo();
		paymentInfo->PaymentNo = iIndex;
		paymentInfo->Balance = CalculateBalance(iIndex);
		paymentInfo->Payment = payment;
		paymentInfo->Interest = CalculateInterestPart(iIndex);
		paymentInfo->Principle = CalculatePrinciple(iIndex);

		lstView->Items->Add(paymentInfo);
	}
}

// Calculate the remaining balance at particular payment
double PaymentWindow::CalculateBalance(int month)
{
	double interestTerm = Math::Pow((1 + interestRate), month);
	double totalInterest = principle * interestTerm;
	double totalPaid = payment * (interestTerm - 1) / interestRate;
	return totalInterest - totalPaid;
}

// Calculate the Interest part of any particular payment
double PaymentWindow::CalculateInterestPart(int month)
{
	double interestTerm = Math::Pow((1 + interestRate), (month - 1));
	double totalInterest = principle * interestTerm;
	double totalPaid = payment * (interestTerm - 1) / interestRate;
	return (totalInterest - totalPaid) * interestRate;
}

// Calculate the principle part of any particular payment
double PaymentWindow::CalculatePrinciple(int month)
{
    return payment - CalculateInterestPart(month);
}