String.Format not converting integers correctly in arabic

Question

I have a problem with String.Format. The following code formats the string correctly apart from the first integer. Current culture is set to Iraqi arabic (ar-IQ):

int currentItem= 1;
string of= "من";
int count = 2;
string formatted = string.Format(CultureInfo.CurrentCulture, "{0}{1}{2}", currentItem, of, count);

The text is formatted right to left and the 2 is converted to an arabic digit, but the 1 isn't.

Any ideas?

Dougdougal

Answer 1

The default behaviour for converting numeric values is "Context", which basically means if a number is proceeded by Arabic they display in Arabic (or another "non-Latin" character), if they're not then they display in "standard" European numbers.

You can change that behaviour quite easily though:

var culture = CultureInfo.CurrentCulture;
culture.NumberFormat.DigitSubstitution = DigitShapes.NativeNational; // Always use native characters
string formatted = string.Format(culture, "{0:d}{1:d}{2:d}", currentItem, of, count);

That should work as you expect - more details on MSDN.

Cindelyn

Cool! This also fixes timespan formatting, ie {0:mm\:ss} in arabic for some reason. With digit substitution a formatting error occurs. – Entanglement

It has been stated on MSDN that DigitSubstitution doesn't have any effect any is reserved for future use: msdn.microsoft.com/en-us/library/…. How does this solution even work? – Unbutton

This code does fails with "InvalidOperationException: Instance is read-only." unless your code sets CurrentCulture to be non-read only (like ...CurrentThread.CurrentCulture = new CultureInfo("fr-fr") ) and as @Unbutton pointed out even after you get code to run DigitSubstitution has no effect on result... Working sample could be useful i.e. www.ideone.com ... – Selfmortification

Answer 2

I couldn't get either of the other answers to work. This worked for me:

string sOriginal = "1 of 2";
var ci = new CultureInfo("ar-IQ", false);
var nfi = ci.NumberFormat;
string sNative = ReplaceWesternDigitsWithNativeDigits(sOriginal, nfi).Replace("of", "من");

...

private static string ReplaceWesternDigitsWithNativeDigits(string s, NumberFormatInfo nfi)
{
    return s.Replace("0", nfi.NativeDigits[0])
        .Replace("1", nfi.NativeDigits[1])
        .Replace("2", nfi.NativeDigits[2])
        .Replace("3", nfi.NativeDigits[3])
        .Replace("4", nfi.NativeDigits[4])
        .Replace("5", nfi.NativeDigits[5])
        .Replace("6", nfi.NativeDigits[6])
        .Replace("7", nfi.NativeDigits[7])
        .Replace("8", nfi.NativeDigits[8])
        .Replace("9", nfi.NativeDigits[9]);
}

Karena

Answer 3

var culture = CultureInfo.CurrentCulture;
culture.NumberFormat.DigitSubstitution = DigitShapes.NativeNational;

does not work, but the following works:

var culture = new CultureInfo("ar-SA");
culture.NumberFormat = new NumberFormatInfo();
Thread.CurrentThread.CurrentCulture = culture;

Thanks for the hint!!!

Wellbalanced