CODEWITHSUNDEEP
c#.net
Maya Li
Maya Li

Reputation: 9

How to multiply two numbers and get the SUM every two numbers is multiply?

Good day everyone! Hope this work. I have to 2 textboxes and I convert it to integer the num1 and num2. I want to display it into textSubtotal. For example 10 * 10 = 100. I want to multiply another 2 numbers the value is 20 * 20 = 400. Add it to 100 so the answer will be 100 + 400 = 500. But the problem is I received an error in this line textSubtotal.Text = Convert.ToString(float.Parse(textSubtotal.Text) + sum) Input string was not in a correct format. Can somebody help me regarding to my problem?

private void buttonOrder_Click(object sender, EventArgs e)
 {
            float num1, num2, product = 0, sum = 0; 
            num1 = float.Parse(textPrice.Text); 
            num2 = float.Parse(textQuantity.Text); 
            product = num1 * num2; sum = sum + product;
            textSubtotal.Text = Convert.ToString(float.Parse(textSubtotal.Text) + sum);
}

Upvotes: 0

Views: 619

Answers (1)

Patrice Gahide
Patrice Gahide

Reputation: 3754

You don't need to struggle with Textbox string conversions to do that. Use a private field:

private float subTotal = 0;    // this would be a field in your class

private void buttonOrder_Click(object sender, EventArgs e)
{
  float num1 = float.Parse(textPrice.Text); 
  float num2 = float.Parse(textQuantity.Text); 
  subTotal += num1 * num2;

  textSubtotal.Text = subTotal;
}

You should check that the two fields contain actual numeric values (see float.TryParse()). Also, consider using decimal (not float) for this kind of calculations.

Upvotes: 1

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