Usesystem

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace Exámen_Final

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

private void textBox1_TextChanged(object sender, EventArgs e)

{

Limpiar.Enabled = true;

}

private void textBox9_TextChanged(object sender, EventArgs e)

{

}

private void button1_Click(object sender, EventArgs e)

{

articulolb.Items.Add(articulos1.SelectedItem.ToString());

cantlb.Items.Add(cant1.Value);

unidadlb.Items.Add(precio.SelectedItem);

decimal importe;

importe = Convert.ToDecimal(precio.SelectedItem);

importelb.Items.Add(cant1.Value * importe);

articulos1.Text = "";

precio.Text = "";

cant1.Value = 1;

agregar.Enabled = false;

}

private void button5_Click(object sender, EventArgs e)

{

Close();

}

private void articulos1_SelectedIndexChanged(object sender, EventArgs e)

{

Limpiar.Enabled = true; int indice;

indice = articulos1.SelectedIndex;

precio.SelectedIndex = indice;

agregar.Enabled = true;

}

private void Form1_Load(object sender, EventArgs e)

{

agregar.Enabled = false;

quitar.Enabled = false;

Limpiar.Enabled = false;

}

private void precio_SelectedIndexChanged(object sender, EventArgs e)

{

int indice;

indice = articulos1.SelectedIndex;

precio.SelectedIndex = indice;

}

private void quitar_Click(object sender, EventArgs e)

{

int indice;

indice = articulolb.SelectedIndex;

if (indice >= 0)

{

articulolb.Items.RemoveAt(indice);

cantlb.Items.RemoveAt(indice);

unidadlb.Items.RemoveAt(indice);

importelb.Items.RemoveAt(indice);

}

else

{ }

quitar.Enabled = false;

}

private void cantlb_SelectedIndexChanged(object sender, EventArgs e)

{

}

private void articulolb_SelectedIndexChanged(object sender, EventArgs e)

{

quitar.Enabled = true;

}

private void calcular_Click(object sender, EventArgs e)

{

int i;

double sub = 0;

for (i = 0; i < importelb.Items.Count; i++)

{

sub += Convert.ToDouble(importelb.Items[i]);

}

if (sub != 0)

{

textBox6.Text = string.Format("S/.{0:F2}", sub);

double a;

a = sub + (sub * 0.18);

textBox9.Text = sub.ToString();

}

else

{

textBox6.Text = "";

...