How do I programm a language independent double.tryparse?

Question

i got string values representing doubles. (f.e. "1.23"). Always with ".".

If you run the code:

double dDouble =0;
string sDemo ="1.23";
double.TryParse(sDemo,out dDouble));

it will return 1.23 to the dDouble var.

If i switch to a different languge with "," as "." .... i get 123.0 as dDouble.

How do I ensure that its always 1.23 ...

double dDouble =0;
string sDemo ="1.23";
double.TryParse(sDemo,System.Globalization.NumberStyles.Any, 
       System.Globalization.CultureInfo.InvariantCulture, out dDouble));

but I am unsure, if this will solve the problem permanently.

i just tried

Using the InvariantCulture *is* the recommended way of writing locale-agnostic conversions of numbers and dates. — Panagiotis Kanavos, Nov 21 '14 at 11:14
In both the end(`double.TryParse` and `double.ToString`), you need to use same culture. — Sriram Sakthivel, Nov 21 '14 at 11:20
Do you know the language/culture/format that was used as the double was written as string? If not then you don't stand a chance to parse it correctly. You could try-parse the whole file(or whatever it is) and look which was more successful. — Tim Schmelter, Nov 21 '14 at 11:46
To the questions: Original format: English, but's a proprietary software ... no .Net. Language: German / English / Chineese — lost bit, Nov 21 '14 at 13:44
So I will stay with the InvariantCulture statement. Is this Invariant Culture based on the Englisch one? — lost bit, Nov 21 '14 at 13:47
@lostbit, ask that question google directly ;) [Click](http://stackoverflow.com/q/9760237/1997232), [click](http://stackoverflow.com/q/2423377/1997232) ... — Sinatr, Nov 21 '14 at 13:54

score 3 · Accepted Answer · answered Nov 21 '14 at 13:07

10 years ago I would solve it like this (do not do that):

sDemo = sDemo.Replace(",",".");

Now

// to string
var text = someDouble.ToString(NumberFormatInfo.InvariantInfo);
// and back
var number = double.Parse(text, NumberFormatInfo.InvariantInfo);

Key point is to use same culture. If you convert values for internal use (to example, passing double value as a part of text) - use invariant culture. If, however, you want to display it to the user and then read user input, then still use same culture: if you don't specify culture for ToString, then don't specify it for Parse, and if you did, then do it again.

How do I programm a language independent double.tryparse?

1 Answers1