private void Form_Load(object sender, EventArgs e)
{
this.calc = new Calc(1000.00, 0.00, 0.0265, 12, 0.00);
this.targetField = 3;
this.targetService = 1;
this.services = new List<CalcService>();
this.services.Add(new SimpleCalcService());
this.services.Add(new CompoundCalcService());
this.calcTarget(this.calc);
this.modelToView(this.calc);
}
private void calcTarget(Calc calc)
{
this.service = this.services.ElementAt(this.targetService);
switch (targetField)
{
case 0:
this.service.InitialAmount(calc);
break;
case 1:
this.service.MonthQtd(calc);
break;
case 2:
this.service.InterestRate(calc);
break;
case 3:
this.service.TotalAmount(calc);
break;
}
}
public void TotalAmount(Calc calc)
{
// M = C * (1 + i) ^ t
calc.TotalAmount = calc.InitialAmount * Math.Pow(1 + calc.InterestRate, calc.MonthQtd);
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
public void MonthQtd(Calc calc)
{
// t = ln(M / C) / ln(1 + i)
calc.MonthQtd = Convert.ToInt32(Math.Log(calc.TotalAmount / calc.InitialAmount) / Math.Log(1 + calc.InterestRate));
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
public void InterestRate(Calc calc)
{
// i = exp(ln(M / C) / t) - 1
calc.InterestRate = Math.Exp(Math.Log(calc.TotalAmount / calc.InitialAmount) / calc.MonthQtd) - 1;
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
public void InitialAmount(Calc calc)
{
// C = M / (1 + i) ^ t
calc.InitialAmount = (calc.TotalAmount / Math.Pow(1 + calc.InterestRate, calc.MonthQtd));
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
public void TotalAmount(Calc calc)
{
// M = C * ( 1 + ( i * t ))
calc.TotalAmount = calc.InitialAmount * (1 + (calc.InterestRate * calc.MonthQtd));
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
public void MonthQtd(Calc calc)
{
// t = ( M / C - 1 ) / i
calc.MonthQtd = Convert.ToInt32((calc.TotalAmount / calc.InitialAmount - 1) / calc.InterestRate);
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
public void InterestRate(Calc calc)
{
// i = ( M / C - 1 ) / t
calc.InterestRate = (calc.TotalAmount / calc.InitialAmount - 1) / calc.MonthQtd;
calc.InstallmentAmount = calc.TotalAmount / calc.MonthQtd;
}
private void viewToModel(Calc calc)
{
calc.InitialAmount = txtInitialAmount.Text != "" ? Double.Parse(txtInitialAmount.Text, NumberStyles.Currency) : 0.00;
calc.InterestRate = txtInterestRate.Text != "" ? Double.Parse(txtInterestRate.Text, NumberStyles.Float) / 100 : 0.00;
calc.MonthQtd = txtMonthQtd.Text != "" ? Int32.Parse(txtMonthQtd.Text) : 0;
calc.TotalAmount = txtTotalAmount.Text != "" ? Double.Parse(txtTotalAmount.Text, NumberStyles.Currency) : 0.00;
calc.InstallmentAmount = txtInitialAmount.Text != "" ? Double.Parse(txtInstallmentAmount.Text, NumberStyles.Currency) : 0.00;
this.radioToTargetField();
this.radioToTargetService();
}
private void modelToView(Calc calc)
{
txtInitialAmount.Text = calc.InitialAmount.ToString("C2");
txtInterestRate.Text = Convert.ToString(calc.InterestRate * 100);
txtMonthQtd.Text = Convert.ToString(calc.MonthQtd);
txtTotalAmount.Text = calc.TotalAmount.ToString("C2");
txtInstallmentAmount.Text = calc.InstallmentAmount.ToString("C2");
this.targetFieldToRadio();
this.targetServiceToRadio();
this.updateDataGrid();
}