Convert decimal to currency and back

[Caleb_83]

It's a little more complicated than that, but this is my code:

    private void button1_Click(object sender, EventArgs e)
    {
        Decimal num1 = Convert.ToDecimal(textBox1.Text);

        Decimal num2 = Convert.ToDecimal(textBox2.Text);

        Decimal total = num1 + num2;

        textBox3.Text = total.ToString("C");

        Decimal total2 = Convert.ToDecimal(total);

        total2 = total * 4.2;

        textBox4.Text = Convert.ToString(total2);

Basically it's this: I have 4 text boxes, and I want to be able to put in a number in box1 and box2. Box three will multiply box 1 & 2 and convert it to currency. Box four will take Box 3s value and change it back to decimal and multiply a number. I can get it to work as long as total2 does not have a decimal. When it has one it will fail.

The program is basically a cash register program that you put in the following:

QTY (box 1)
Amonunt (box 2)
Subtotal (box 3)
Total (box 4)

Any ideas will be helpful.

Thanks,

Caleb