How to set Million separator (') and thousand (.) using cultureinfo in C#

Question

I'm trying to convert a value 9.999.999 to 9'999.999 using cultureinfo in C# but I can't get it works.

How can I do that?

Answer 1

So it's a string and you want a different group-separator for first groups?

You could replace all but the last dot:

string value = "9.999.999";
StringBuilder sb = new StringBuilder(value);
bool skippedLast = false;

for (int i = sb.Length - 1; i >= 0; i--)
{
    if (sb[i] == '.')
    {
        if (!skippedLast)
            skippedLast = true;
        else
            sb[i] = '\'';
    }
}

string desiredOutput = sb.ToString(); // 9'999.999

Answer 2

since the default IFormatProvider implementations that are shipped with the framework lack the capability you want/need, I suggest implementing the interface yourself

additionally, since CultureInfo is not sealed, you can extend the class and provide your implementation to System.Threading.Thread.CurrentThread.CurrentCulture ... all consecutive formatting calls on that thread will use your implementation (unless called with a specific format provider...)