using System;

public class Program

{

    public static void Main()

    {

        var ret = MyFunction("hello:");

        Console.WriteLine( ret );

​

    }

    public enum MyEnum

    {

        Test=1,

        MyDefaultValue=1,

    }

    public static string MyFunction(string param1, MyEnum param2 = MyEnum.MyDefaultValue)

    {    // Do something...

        Console.WriteLine( param2 );

        return param1 + param2;

    }

}