CSharp

Hi Guys,

I have some windows form application that I built for testing and learning.

The application looks like:
app
The purpose is to calculate between Height and weight which actually work fine.  the issue I get is when user doesn't type anythingin the textbox fields he gets an exception {"Input string was not in a correct format."}.

Here is my code:

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnshow_Click(object sender, EventArgs e)
        {  
                string Name = textname.Text;
                int Height = Convert.ToInt32(textheight.Text);
                double Weight = Convert.ToDouble(textweight.Text);
            

                BMI obj1 = new BMI(Name, Height,Weight);
                {
                    MessageBox.Show
                        ("Name: " + obj1.getName() + Environment.NewLine + "Height: " + obj1.getHights() + Environment.NewLine + "Weight: " + obj1.getWeight() + Environment.NewLine + "Calculation: " + obj1.CalculateBMI());
                }
         



        }

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LVL 1
Moti Mashiah.NET DeveloperAsked:
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p_davisCommented:
private void btnshow_Click(object sender, EventArgs e)
        {  
                string Name = textname.Text;
                if(!String.IsNullOrEmpty(Name))
{
.....
}
p_davisCommented:
just need to check  for empty  or null string, i would think
Moti Mashiah.NET DeveloperAuthor Commented:
Yes, I know but how to do it?

I'm very new and just learning.
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Moti Mashiah.NET DeveloperAuthor Commented:
K,

I did something like this:
and now I'm getting error on the "int Height" {"Input string was not in a correct format."}
 
            string Name = textname.Text;
            if (!string.IsNullOrEmpty(Name))
            {
                MessageBox.Show("Enter Name");
            }
            int Height = Convert.ToInt32(textheight.Text);
            double Weight = Convert.ToDouble(textweight.Text);
p_davisCommented:
Just add a return; if within the null empty check
p_davisCommented:
wait... one minute -- i was using my phone... now at my computer.
p_davisCommented:
i was using ! ( the not symbol for c) to check if the string want' null or empty then continue with using it..... you have it as if isn't null or empty then give a message.... if you are going to use it in the way of if it is null or empty then provide user input you need to take away the !


otherwise, i think this is what you might want

private void btnshow_Click(object sender, EventArgs e)
        {  
                string Name = textname.Text;
if(!string.IsNullOrEmpty(Name)
{
                int Height = Convert.ToInt32(textheight.Text);
                double Weight = Convert.ToDouble(textweight.Text);
            

                BMI obj1 = new BMI(Name, Height,Weight);
                {
                    MessageBox.Show
                        ("Name: " + obj1.getName() + Environment.NewLine + "Height: " + obj1.getHights() + Environment.NewLine + "Weight: " + obj1.getWeight() + Environment.NewLine + "Calculation: " + obj1.CalculateBMI());
                }
}
else
{
    MessageBox.Show("Enter Name");
}



        }

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Moti Mashiah.NET DeveloperAuthor Commented:
k, that works when all my fields are empty, but what if user insert Name but doesn't insert the other to fields "Height" and "Weight"?

it is going to fail again. like it happens to me now.
Moti Mashiah.NET DeveloperAuthor Commented:
Please, review the code and see what I mean.
If you insert to textname and leave the other fields empty, you are going to get an exception.

private void btnshow_Click(object sender, EventArgs e)
        {

            string Name = textname.Text;
            if (!string.IsNullOrEmpty(Name))
            {
                int Height = Convert.ToInt32(textheight.Text);
                double Weight = Convert.ToDouble(textweight.Text);

                BMI obj1 = new BMI(Name, Height, Weight);
                MessageBox.Show
                    ("Name: " + obj1.getName()
                    + Environment.NewLine
                    + "Height: "
                    + obj1.getHights()
                    + Environment.NewLine
                    + "Weight: "
                    + obj1.getWeight()
                    + Environment.NewLine
                    + "Calculation: "
                    + obj1.CalculateBMI());

            }

            else
            {
                MessageBox.Show("Please, you have to insert details in all fields");
            }

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Franck GaspozSoftware Architect, Technical ExpertCommented:
Hi,
you can use TryParse methods which avoids to have to test exceptions, by this way :

int Height;
double Weight;
if ( Int32.TryParse(textheight.Text,out Height) && Double.TryParse(textweight.Text,out Weight)) {
  // both strings are valid, variables Height and Weight are initialized
  BMI obj1 = ...
} else
  // eventually display a message here
 ...

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Moti Mashiah.NET DeveloperAuthor Commented:
Solved my issue.
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