Question

I have a form that has two buttons, textbox, listbox, and a combobox. The problem I am having is when I am trying to total button. I can not figure out how to get the cost values from this list, so I can total the total cost of the order. Thanks for the suggestions.

    private void Order_Click(object sender, EventArgs e)
    {
        amount = int.Parse(textBox1.Text);
        cost *= amount;

        if (comboBox1.SelectedItem.ToString() == "Eggs")
        {
            listBox1.Items.Add("The cost for  " + amount + " 
            dozen large, fresh eggs is: " + (cost).ToString("C"));
            comboBox1.Text = "";
            textBox1.Text = "0";
            textBox1.Focus();
            comboBox1.Focus();
        }
        else if (comboBox1.SelectedItem.ToString() == "Milk")
        {
            if (amount == 1)
            {
                listBox1.Items.Add
                ("The Cost for a fresh quart milk is: " + (cost).ToString("C"));
                comboBox1.Text = "";
                comboBox1.Focus();
                textBox1.Text = "0";
                textBox1.Focus();
            }
            else
            {
                listBox1.Items.Add
            ("The Cost for " + amount + "  quarts of fresh milk is: " + 
                (cost).ToString("C"));
                comboBox1.Text = "";
                comboBox1.Focus();
                textBox1.Text = "0";
                textBox1.Focus();
            }
        }
        else
        {
            listBox1.Items.Add
             ("The Cost for " + amount + " fresh loafs of bread is: " + (cost).ToString("C"));
            comboBox1.Text = "";
            comboBox1.Focus();
            textBox1.Text = "0";
            textBox1.Focus();
        }
    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (comboBox1.SelectedItem.ToString() == "Eggs")
        {
            cost = 1.90;
            label1.Text = "The Cost is " + (cost).ToString("C") + " per dozen";
        }
        else if (comboBox1.SelectedItem.ToString() == "Milk")
        {
            cost = 1.47;
            label1.Text = "The Cost is " + (cost).ToString("C") + " per quart";
        }
        else
        {
            cost = 2.12;
            label1.Text = "The Cost is " + (cost).ToString("C") + " per loaf";
        }
    }

    private void total_Click(object sender, EventArgs e)
    {


    }

    private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!char.IsControl(e.KeyChar)
            && !char.IsDigit(e.KeyChar)
            && e.KeyChar != '.')
        {
            e.Handled = true;
        }

        if (e.KeyChar == '.'
    && (sender as TextBox).Text.IndexOf('.') > -2)
        {
            e.Handled = true;
        }
        if (e.KeyChar == '-'
 && (sender as TextBox).Text.IndexOf('-') > -2)
        {
            e.Handled = true;
        }
    }
}

}

Answer 1

Why not use a total class field and add the amount to it each time you add an item to the list box? Then you would always have the total cost without having to try to parse it back out of the list.

public partial class Form1 : Form
{
    private double cost;
    private double total;
    int amount = 0;

    public Form1()
    {
        InitializeComponent();
    }

    private void Order_Click(object sender, EventArgs e)
    {
        amount = int.Parse(textBox1.Text);
        cost *= amount;
        total += cost;
        ...
    }