'How do I create a custom error message with a try/catch block in C#?

I'm doing a simple order total calculation function and I'm trying to figure out how to display a custom error message when the user input is the incorrect format. I.e. when they enter a non-integer in txtJava.Text, the message will display "Please enter an integer for Java"

    private void btnSubmit_Click(object sender, EventArgs e)
    {
        
        int Java;
        int Latte;
        int Mocha;
        int Frappe; 
        string Name = txtName.Text;
        double javaPrice = 1.25;
        double mochaPrice = 2.95;
        double lattePrice = 2.75;
        double frappePrice = 3.25;
        double dblTaxRate = .09;
        double dblSubtotal;
        double dblTax;
        double dblTotal;

        txtMessage.Text = "Thank you " + Name + " for your order!";
        
        Java = Convert.ToInt32(txtJava.Text);
        Latte = Convert.ToInt32(txtLatte.Text);
        Mocha = Convert.ToInt32(txtMocha.Text);
        Frappe = Convert.ToInt32(txtFrappe.Text);
        dblSubtotal = Java * javaPrice + Mocha * mochaPrice + Frappe * frappePrice + Latte * lattePrice;
        dblTax = dblSubtotal * dblTaxRate;
        dblTotal = dblSubtotal + dblTax;

        txtSubtotal.Text = dblSubtotal.ToString("C2");
        txtTax.Text = dblTax.ToString("C2");
        txtTotal.Text = dblTotal.ToString("C2");
c++sharpvisual-studio


Solution 1:[1]

Avoid using try Prase or try catch in this scenario. It is better to change the textbox input type to be a number only.

I can't see what type of application you are running, but if its a webForms application you could alter the markup to look something like this:

<input type="number" id="quantity" name="quantity" min="1" max="100">

If its a WPF application: Allow only numeric entry in WPF Text Box

If this doesn't help you may need to provide more code. Give us a bit more context.

Happy coding.

Solution 2:[2]

This code, instead of Java = Convert.ToInt32(txtJava.Text);

if (!TryParse(txtJava.Text, Java)) {
      //Display the text you want
}

In addition, your variables are not with the same naming convention ;)

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 DharmanBot
Solution 2 Dylan Barquilla

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