I want to write a loan calculator. A user gets to choose a car model, and the calculator will calculate the monthly installment for that car based on user input down payment and interest rate.
But when I click the calculate button it shows a message box and says
input string was not in a correct form
You can check the button click event at the bottom of the code.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Proton_System
{
public partial class Loan_Calculator : Form
{
public Loan_Calculator()
{
InitializeComponent();
}
//Add Items into combobox2 and combobox4 when combobox1 is selected with specific car models
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox1.SelectedItem == "Persona")
{
comboBox2.Items.Clear();
comboBox2.Items.Add("1.6L Standard CVT");
comboBox2.Items.Add("1.6L Executive CVT");
comboBox2.Items.Add("1.6L Premium CVT");
comboBox4.Items.Clear();
comboBox4.Items.Add("Peninsular Malaysia");
comboBox4.Items.Add("East Malaysia");
comboBox4.Items.Add("Labuan");
comboBox4.Items.Add("Langkawi");
}
else if (comboBox1.SelectedItem == "X50")
{
comboBox2.Items.Clear();
comboBox2.Items.Add("1.5T Standard");
comboBox2.Items.Add("1.5T Executive");
comboBox2.Items.Add("1.5T Premium");
comboBox2.Items.Add("1.5TGDi Flagship");
comboBox4.Items.Clear();
comboBox4.Items.Add("Peninsular Malaysia");
comboBox4.Items.Add("East Malaysia");
}
else
{
comboBox2.Items.Clear();
comboBox2.Items.Add("1.8TGDi Standard");
comboBox2.Items.Add("1.8TGDi Executive");
comboBox2.Items.Add("1.8TGDi Premium");
comboBox2.Items.Add("1.8TGDi Premium X");
comboBox4.Items.Clear();
comboBox4.Items.Add("Peninsular Malaysia");
comboBox4.Items.Add("East Malaysia");
comboBox4.Items.Add("Labuan");
comboBox4.Items.Add("Langkawi");
}
}
//Add Items into combobox3 when combobox2 is selected with specific variants
private void comboBox2_SelectedIndexChanged(object sender, EventArgs e)
{
if (comboBox2.SelectedItem == "1.6L Standard CVT")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Ruby Red");
comboBox3.Items.Add("Rose Wood Maroon");
}
else if (comboBox2.SelectedItem == "1.6L Executive CVT")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Ruby Red");
comboBox3.Items.Add("Rose Wood Maroon");
}
else if (comboBox2.SelectedItem == "1.6L Premium CVT")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Ruby Red");
comboBox3.Items.Add("Rose Wood Maroon");
}
else if (comboBox2.SelectedItem == "1.5T Standard")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Ocean Blue");
}
else if (comboBox2.SelectedItem == "1.5T Executive")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Critic Orange");
comboBox3.Items.Add("Ocean Blue");
}
else if (comboBox2.SelectedItem == "1.5T Premium")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Passion Red");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Critic Orange");
comboBox3.Items.Add("Ocean Blue");
}
else if (comboBox2.SelectedItem == "1.5T Premium X")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Passion Red");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Critic Orange");
comboBox3.Items.Add("Ocean Blue");
}
else if (comboBox2.SelectedItem == "1.8TGDi Standard")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
}
else if (comboBox2.SelectedItem == "1.8TGDi Executive")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Ruby Red");
comboBox3.Items.Add("Cinnamon Brown");
}
else if (comboBox2.SelectedItem == "1.8TGDi Premium")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Ruby Red");
comboBox3.Items.Add("Space Grey");
comboBox3.Items.Add("Cinnamon Brown");
}
else if (comboBox2.SelectedItem == "1.8TGDi Premium X")
{
comboBox3.Items.Clear();
comboBox3.Items.Add("Snow White");
comboBox3.Items.Add("Jet Grey");
comboBox3.Items.Add("Armour Silver");
comboBox3.Items.Add("Ruby Red");
comboBox3.Items.Add("Space Grey");
comboBox3.Items.Add("Cinnamon Brown");
}
}
//Change label9 text when selected combobox4 and combobox2
private void comboBox4_SelectedIndexChanged(object sender, EventArgs e)
{
//Set label 9 text to persona 1.6 standard price based on region choosen
if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.6L Standard CVT")
{
label9.Text = "RM45800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.6L Standard CVT")
{
label9.Text = "RM47,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.6L Standard CVT")
{
label9.Text = "RM47,100";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.6L Standard CVT")
{
label9.Text = "RM45,200";
}
//Set label 9 text to persona 1.6 executive price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.6L Executive CVT")
{
label9.Text = "RM50,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.6L Executive CVT")
{
label9.Text = "RM52,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.6L Executive CVT")
{
label9.Text = "RM51,200";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.6L Executive CVT")
{
label9.Text = "RM49,400";
}
//Set label 9 text to persona 1.6 premium price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.6L Premium CVT")
{
label9.Text = "RM55,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.6L Premium CVT")
{
label9.Text = "RM57,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.6L Premium CVT")
{
label9.Text = "RM56,300";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.6L Premium CVT")
{
label9.Text = "RM54,500";
}
//Set label 9 text to X50 1.5T Standard price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.5T Standard")
{
label9.Text = "RM79,200";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.5T Standard")
{
label9.Text = "RM81,200";
}
//Set label 9 text to X50 1.5T Executive price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.5T Executive")
{
label9.Text = "RM84,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.5T Executive")
{
label9.Text = "RM86,800";
}
//Set label 9 text to X50 1.5T Premium price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.5T Premium")
{
label9.Text = "RM93,200";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.5T Premium")
{
label9.Text = "RM95,200";
}
//Set label 9 text to X50 1.5T Premium X price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.5TGDi Flagship")
{
label9.Text = "RM103,300";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.5TGDi Flagship")
{
label9.Text = "RM105,300";
}
//Set label 9 text to X70 1.8TGDi Standard price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.8TGDi Standard")
{
label9.Text = "RM94,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.8TGDi Standard")
{
label9.Text = "RM94,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.8TGDi Standard")
{
label9.Text = "RM90,200";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.8TGDi Standard")
{
label9.Text = "RM88,700";
}
//Set label 9 text to X70 1.8TGDi Executive price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.8TGDi Executive")
{
label9.Text = "RM106,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.8TGDi Executive")
{
label9.Text = "RM106,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.8TGDi Executive")
{
label9.Text = "RM101,800";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.8TGDi Executive")
{
label9.Text = "RM100,300";
}
//Set label 9 text to X70 1.8TGDi Premium price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.8TGDi Premium")
{
label9.Text = "RM119,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.8TGDi Premium")
{
label9.Text = "RM119,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.8TGDi Premium")
{
label9.Text = "RM114,400";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.8TGDi Premium")
{
label9.Text = "RM112,900";
}
//Set label 9 text to X70 1.8TGDi Premium X price based on region choosen
else if (comboBox4.SelectedItem == "Peninsular Malaysia" && comboBox2.SelectedItem == "1.8TGDi Premium X")
{
label9.Text = "RM122,800";
}
else if (comboBox4.SelectedItem == "East Malaysia" && comboBox2.SelectedItem == "1.8TGDi Premium X")
{
label9.Text = "RM122,800";
}
else if (comboBox4.SelectedItem == "Labuan" && comboBox2.SelectedItem == "1.8TGDi Premium X")
{
label9.Text = "RM117,300";
}
else if (comboBox4.SelectedItem == "Langkawi" && comboBox2.SelectedItem == "1.8TGDi Premium X")
{
label9.Text = "RM115,800";
}
}
private void button1_Click(object sender, EventArgs e)
{
int amount, pay, afterprinciple, down, totalinterest, duration, year= 0;
double rate= 0;
try
{
rate = Convert.ToDouble(textBox2.Text);
year = Convert.ToInt16(comboBox5.Text);
duration = Convert.ToInt16(comboBox5.Text) * 12;
amount = Convert.ToInt16(label9.Text);
down = Convert.ToInt16(textBox1.Text);
if (rate > 1)
{
rate = rate / 100;
}
afterprinciple = amount - down;
totalinterest = (int)(rate * (afterprinciple) * year);
pay = (afterprinciple totalinterest) / duration;
label14.Text = pay.ToString();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}
CodePudding user response：
Start with something like this:
<cars>
<type name="Persona">
<model name="1.6L Standard CVT">
<location name="Peninsular Malaysia" price="45800"/>
<location name="East Malaysia" price="47800"/>
<location name="Labuan" price="47100"/>
<location name="Langkawi" price="45200"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Ruby Red"/>
<colour name="Rose Wood Maroon"/>
</model>
<model name="1.6L Executive CVT">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<location name="Labuan" price="1"/>
<location name="Langkawi" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Ruby Red"/>
<colour name="Rose Wood Maroon"/>
</model>
<model name="1.6L Premium CVT">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<location name="Labuan" price="1"/>
<location name="Langkawi" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Ruby Red"/>
<colour name="Rose Wood Maroon"/>
</model>
</type>
<type name="X50">
<model name="1.5T Standard">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Ocean Blue"/>
</model>
<model name="1.5T Executive">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Critic Orange"/>
<colour name="Ocean Blue"/>
</model>
<model name="1.5T Premium">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Passion Red"/>
<colour name="Armour Silver"/>
<colour name="Critic Orange"/>
<colour name="Ocean Blue"/>
</model>
<model name="1.5TGDi Flagship">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Passion Red"/>
<colour name="Armour Silver"/>
<colour name="Critic Orange"/>
<colour name="Ocean Blue"/>
</model>
</type>
<type name="???">
<model name="1.8TGDi Standard">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<location name="Labuan" price="1"/>
<location name="Langkawi" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
</model>
<model name="1.8TGDi Executive">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<location name="Labuan" price="1"/>
<location name="Langkawi" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Ruby Red"/>
<colour name="Cinnamon Brown"/>
</model>
<model name="1.8TGDi Premium">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<location name="Labuan" price="1"/>
<location name="Langkawi" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Ruby Red"/>
<colour name="Space Grey"/>
<colour name="Cinnamon Brown"/>
</model>
<model name="1.8TGDi Premium X">
<location name="Peninsular Malaysia" price="1"/>
<location name="East Malaysia" price="1"/>
<location name="Labuan" price="1"/>
<location name="Langkawi" price="1"/>
<colour name="Snow White"/>
<colour name="Jet Grey"/>
<colour name="Armour Silver"/>
<colour name="Ruby Red"/>
<colour name="Space Grey"/>
<colour name="Cinnamon Brown"/>
</model>
</type>
</cars>
Learn how to load that into memory as data. Everything from there on should be just looking up the data that loaded into memory. There should be no Convert.To*** code for the data you've loaded from this file.