converting string from a textbox to a double not working in c#

Question

okay so I'm really confused about this problem and I don't know how to fix it. this is the code and I cant see what I did wrong:

        private void btnFormule_Click(object sender, EventArgs e)
        {

            double NumberA;
            NumberA = double.Parse(txtA.Text);

        }

it also does the same if I do convert.todouble(). But the weird thing is a while ago it didn't give an error when I did it like this so I don't know what's going on.

When I try it out it gives the error "System.FormatException: The format of the input string is incorrect" (its translated so it's not the exact error). if anyone has a solution to this problem it would really help

I suggest to use double.TryParse instead of double.Parse since not every string could be converted to a double, also you should take care about the current culture when parsing see here — Stefano Cavion
– Stefano Cavion, Commented Feb 7, 2020 at 11:14
As per the docs for double.Parse() you'll get a FormatException if the string you're passing does not represent a valid format — Ian
– Ian, Commented Feb 7, 2020 at 11:16
Check if it's a locale issue. Probably the decimal separator you're using is different from what the system expects. Use double.Parse(string s, IFormatProvider provider) — Magnetron
– Magnetron, Commented Feb 7, 2020 at 11:17
I like using Convert class and just wrap it into try/catch so function from it you need would be Convert.ToDouble(object) — Aleksa Ristic
– Aleksa Ristic, Commented Feb 7, 2020 at 11:18
@AleksaRistic Convert is nothing more than a wrapper for double.Parse. It fails exactly the same way if the format is wrong. It accepts a CultureInfo too. — Panagiotis Kanavos
– Panagiotis Kanavos, Commented Feb 7, 2020 at 11:29

Stefano Cavion · Accepted Answer · 2020-02-07 11:26:19Z

1

You should use a combination of double.TryParse and CultureInfo

  private void btnFormule_Click(object sender, EventArgs e)
  {

      if(double.TryParse( textA.Text,NumberStyles.Any, CultureInfo.CurrentCulture, out double NumberA);
      {
        //Manage the valid parsing;
      }
      else
      {
        //Manage the not valid parsing
      }


    }

answered Feb 7, 2020 at 11:26

Stefano Cavion

7418 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Panagiotis Kanavos Over a year ago

CultureInfo.CurrentCulture is the default

Stefano Cavion Over a year ago

you are right but here I don't know which is the problem with that string since the op didn't post it. I could suppose that the problem is on the decimal/thousand separator since this is different in many Culture. Of course he can set the culture to use instead of the current culture

Collectives™ on Stack Overflow

converting string from a textbox to a double not working in c#

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related