Query string with dot as decimal separator in C#

Question

I would like to build a query string with a dot as decimal separator but I can not figure out how / where I should use the CultureInfo to convert the comma to the dot in the Account property value.

Person person = new()
{
    Name = "Tom",
    Account = 1000.123m,
};

var properties = from p in person.GetType().GetProperties()
                 where p.GetValue(person, null) != null
                 select p.Name.ToLower() + "=" + p.GetValue(person);

Console.WriteLine(String.Join("&", properties.ToArray()));


class Person
{
    public string Name { get; set; } = String.Empty;
    public decimal Account { get; set; }
}

Current output: name=Tom&account=1000,123

Expected output: name=Tom&account=1000.123

I guess there is something to add to + p.GetValue(person)

Can you help me please? Many thanks.

Answer 1

To format numeric property values using a period instead of a comma for the decimal separator, call Convert.ToString(Object, IFormatProvider) and pass the invariant culture as the second argument:

using System.Globalization;

// ...

select p.Name.ToLower() + "=" + Convert.ToString(p.GetValue(person), CultureInfo.InvariantCulture);

// or you can use string interpolation:
// select FormattableString.Invariant($"{p.Name.ToLower()}={p.GetValue(person)}");

This particular overload of Convert.ToString calls IConvertible.ToString, IFormattable.ToString, or just Object.ToString depending on the interfaces implemented by the value.

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By the way, for the property name, you should call String.ToLowerInvariant instead of ToLower to avoid the Turkish "i" problem: In the tr-TR culture, "I".ToLower() returns "ı" (dotless i) instead of "i". You should also ensure that special characters in the property value are correctly encoded in the query string:

select p.Name.ToLowerInvariant() + "=" +
    Uri.EscapeDataString(Convert.ToString(p.GetValue(person), CultureInfo.InvariantCulture)!);