Question

Problem 6.3 Sum of Numbers - Similar to Problems 6.1 & 6.2, you must sum up 5 numbers. However, you will obtain these numbers from a list box for which you have used the String Collection Editor to insert a number on each of 5 lines in the box. You may use any type of loop. The result is displayed in a text box. The program is initiated with "Go" button.

Problem 6.3 does NOT require an Input Dialog Box. Instead, YOU the PROGRAMMER put a list box control on the form. The PROGRAMMER loads up the list box at design time with all five (5) numbers to be summed.

Answer 1

Step1: Create a C# WindowsFormApplication and set a name of your choice.

Step2: Design the form with ListBox, Button and TextBox as shown in the below screenshot

Step3:

Set the following properties of the controls on the form

Step4:

Double click the Go button and write the below code

Code:

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 SumupCollection
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnGo_Click(object sender, EventArgs e)
        {
            //Create an array of string objects
            String[] nums = new String[5];
            nums[0] = "1";
            nums[1] = "2";
            nums[2] = "3";
            nums[3] = "4";
            nums[4] = "5";
            //Add listbox elements to the listbox1
            listBox1.Items.AddRange(nums);
            double total = 0;
            //use foreach loop to find the total of the itesm in the listBox1
            foreach (String item in listBox1.Items)
            {
                total = total + int.Parse(item);
            }
            //Show the total value in result text box
            resultTxtBox.Text = total.ToString();
        }
    }
}

Step5:

Run the application :Output