WPF C# string to decimal, decimal to string problem

Question

Please, help me to identify problem in my C# code(WPF, event-handler):

        private void Discount5Btn_Click(object sender, RoutedEventArgs e)
    {
        decimal catPr;
        decimal salePr;
        string catPrStr;
        catPrStr = PriceCatTBox.Text;
        catPr = decimal.Parse(catPrStr);
        salePr = decimal.Multiply(catPr, 0.95m);
        SalePriceTBox.Text = (salePr).ToString("0000.00");
    }

I can not make it work - debugger shows error on catPr = decimal.Parse(catPrStr); . Very similar code in another place works. And am I right in such an approach to string-decimal conversion for arithmetic operation?

Edit (added)

Sorry for not specifying catPrStr value, it is from textbox in the following code (in another event-handler):

dlg.PriceCatTBox.Text = "2300.00";
....

and then as above:

catPrStr = PriceCatTBox.Text;

Answer 1

We can't help you because we don't know the value of catPrStr, you are converting from String to Decimal and most likely the value of the string being converted is incorrect.

Answer 2

decimal.TryParse(catPrStr, out catPr); and handle the bool return from it to ensure that you have a reasonable value to process.

Answer 3

And am I right in such an approach to string-decimal conversion for arithmetic operation?

I would set up two way binding with a model to store your decimal values. This will allow you to access them directly instead of parsing strings. This will also solve your error.

Answer 4

Are you sure your culture (locale) settings aren't interfering? If catPrStr is always in the invariant culture shown in your edited question, you could use decimal.TryParse(catPrStr, CultureInfo.InvariantCulture); to force the usage of that culture. If the culture isn't specified, parsing is done in the current system culture, which might, for example, use a comma as the decimal separator.