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CSharp · Console

/Program.cs

using System;

public enum CountryCode
{
    Undefined = default,
    DK = 10,
    PL = 20
}

public class Program
{
	public static void Main()
	{
		Console.WriteLine(Enum.Parse<CountryCode>("DK"));
		Console.WriteLine(Enum.Parse<CountryCode>("10"));
		Console.WriteLine(Enum.IsDefined(Enum.Parse<CountryCode>("10")));
	}
}