单击 ListBox 项目并获取它们的值并添加到小计

Question

I'm working on a project right now and I've run across a curious thing that I don't have enough knowledge in to solve.

I have a private const decimal listed below which is the value of each item in the list box. For each item in the listbox clicked, I would like to add it to my subtotal automatically.

How can I go about clicking a listbox item and having the corresponding price ($9.50) go into the Subtotal textbox.

Please let me know if I could provide more detail to solve this.

            private const decimal EXTRAS = 9.50m;

            subtotalPrice = deliveryTypePrice + balloonAmount + messagePrice + listBoxItemsPriceTotal;
            salesTaxPrice = subtotalPrice * TAX_RATE;
            totalPrice = subtotalPrice + salesTaxPrice;

            subtotalTextBox.Text = subtotalPrice.ToString("c");
            salesTaxTextBox.Text = salesTaxPrice.ToString("c");
            orderTotalTextBox.Text = totalPrice.ToString("c");

Answer 1

Hey this is quite simple. Don't try to use ToString() because it is more for formatting as string than be written as string.

You can just use it as followed:

private const decimal EXTRAS = 9.50m;

subtotalPrice = deliveryTypePrice + balloonAmount + messagePrice + listBoxItemsPriceTotal;
salesTaxPrice = subtotalPrice * TAX_RATE;
totalPrice = subtotalPrice + salesTaxPrice;

subtotalTextBox.Text = "" + subtotalPrice.ToString("c");
salesTaxTextBox.Text = "" + salesTaxPrice.ToString("c");
orderTotalTextBox.Text = "" + totalPrice.ToString("c");

I didn't test it so it could be that you need to delete the ToString("c") because there will be written crap. If that is the Case then use ("" + totalPrice).ToString("c"); if you still need to format. If not just delete ToString()

Answer 2

If you want to the value of the item you clicked, you can achieve it by subscribing to MouseClick event. And then get the value by property SelectedItem .

Here is a demo.

public Form1()
{
    InitializeComponent();
    // Subscribe to "MouseClick"
    listBox1.MouseClick += listBox1_MouseClick;
}

private void Form1_Load(object sender, EventArgs e)
{
    List<decimal> list = new List<decimal> { 1.2m, 3.4m, 6.3m };
    listBox1.DataSource = list;
}

private void listBox1_MouseClick(object sender, MouseEventArgs e)
{
    // Show the selected value in textbox
    decimal value = (decimal)(listBox1.SelectedItem);
    subtotalTextBox.Text = value.ToString("C");
}

The test result,