Programming a windows form in a mature way

Question

I am very new in C#. I have written a code to get two numbers in two text boxes and basically show their multiplication in a third text box.

The code is like:

private void button1_Click(object sender, EventArgs e)
{
    double A = double.Parse(textBox2.Text); 
    double B = double.Parse(textBox3.Text); //gets the hourly wage
    double C = A * B; 
}

I have written them all in an executing button class. How can I get "A" and "B" in their own private texbox classes and relate them in "C" text box class? I need to do it in order to validate the textboxes to give the user an error if he leaves any textboxes empty.

What you mean by `How can I get "A" and "B" in their own private texbox classes and relate them in "C" text box class?` — Zbigniew, Apr 27 '13 at 13:17
I can't get the point either. What are you trying to accomplish? — Harits Fadillah, Apr 27 '13 at 13:19
Ain't the A and B are already related to "their own private textboxes"?, As you are getting A and B from textBox2 and textBox3 — Khadim Ali, Apr 27 '13 at 13:23
Probably this comment will get deleted, but I will go as far as to say that in you investigate what [MVVM](http://stackoverflow.com/questions/14381402/wpf-programming-methodology/14382137#14382137) is, you'll realize that winforms doesn't support "mature programming" and that you need more advanced and modern technologies for that. — Federico Berasategui, Apr 27 '13 at 13:41

score 0 · Answer 1 · answered Apr 27 '13 at 13:31

0

You may restrict user to fill in the text boxes before executing the button logic in this way:

private void button1_Click(object sender, EventArgs e)
{
    if(textBox2.Text == string.Empty || textBox3.Text == string.Empty)
    {
        MessageBox.Show("Invalid input");
        return;
    }

    double A = double.Parse(textBox2.Text); 
    double B = double.Parse(textBox3.Text); //gets the hourly wage
    double C = A * B; 
}

answered Apr 27 '13 at 13:31

Khadim Ali

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Personally I'd rather use `if(string.IsNullOrWhiteSpace(textBox2.Text))`, so it would check whitespaces too. But, I'm not really sure if this is the answer for this question. – Zbigniew Apr 27 '13 at 13:38
@walkhard I just guessed it from the asker's statement "... I need to do it in order to validate the textboxes to give the user an error if he leaves any textboxes empty." – Khadim Ali Apr 27 '13 at 13:51

score 0 · Answer 2 · answered Apr 27 '13 at 14:20

This is what u do to display your answer in the third textbox

private void button1_Click(object sender, EventArgs e)
{
    if(textBox2.Text == string.Empty || textBox3.Text == string.Empty)
    {
      MessageBox.Show("Please Fill Both Text Box");
      return;
    }

    double A = double.Parse(textBox2.Text); 
    double B = double.Parse(textBox3.Text); 
    textbox4.Text = (A * B).ToString(); 
}

Programming a windows form in a mature way

2 Answers2