Xamarin应用程序可在模拟器上运行，但不能在设备上运行

Question

I´ve done a simple app which convert an amount of Bitcoins to a currency.

The app works fine on my android emulator(Nexus 5x). My problem is that the app throws:

System.FormatException: Input string was not in a correct format

When I test it on my android device. I´ve debuged both my emulator and device and it´s no diffrence in the parameters.

Do someone have any thought why this exception occurs?

public static async Task<decimal> ConvertCurrency(string curr, decimal amount)
    {
        var currency = await GetCurrency(curr);
        var stringRate = currency.Rate;
        var rate = decimal.Parse(stringRate);//this is where the it crash
        var result = rate * amount;
        return result;
    }

Answer 1

That comma delimiter is your problem. You would need to change your parse Method to detect the Current culture and parse using that IFormatProvider

Use the overload(s) of decimal.Parse :

string stringRate = "118,130.4542";
decimal d = decimal.Parse(stringRate, 
                          NumberStyles.Currency, 
                          new CultureInfo("en-Us").NumberFormat);
//Output: 118130.4542M

d = decimal.Parse(stringRate, new CultureInfo("en-Us").NumberFormat);
//Output: 118130.4542M

Answer 2

Most likely that happens because of the language settings on your phone. If you try to parse a string from the web using default decimal.Pars function, it would try to identify the separator based on your language settings (or local, it depends). That mean that if a phone use a "," as a decimal separator, it would try to look for it into input string even if the string come in a format 12.32. To fix that, pass a culture or implicit separator into parser.

decimal.TryParse(EnglishDecimal, out b)