NewFeatureDemoForCSharp6.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace NewFeatures
{
    //1. Using Static Members
    using static System.Math;

    class Foo
    {
        //0. Getter-only auto-properties & Initializer for auto-properties
        //"private set" is not needed anymore for readonly properties
        public string None { get; } = "Nothing";
    }
    class Program
    {
        //3. Expression Bodied properties
        //equals to string GetHating(string a, string b) => { return $"{a} hates {b}."; }
        static string GetHating(string a, string b) => $"{a} hates {b}.";

        //4. Index initializer
        static Dictionary<string, string> GetDic(string a, string b) =>
            new Dictionary<string, string> {
                ["love"] = $"{a} loves {b}."
               ,["hate"] = $"{a} hates {b}."
               ,["kill"] = $"{b} wanna kill {a}."
            };

        static async void DemoException()
        {
            //6. exception filter & await in try...catch...finally
            try
            {
                throw new Exception("Anyway");
            }
            catch(Exception e) when (e.Message.Contains("Anyway"))
            {
                await Task.Delay(1000);
                Console.WriteLine("Exception Caught!");
            }
        }
        static void Main(string[] args)
        {
            //1. Using Static Members continued
            //2. String Interpolation
            Console.WriteLine($"Sqr(4)={Sqrt(4)}");
            
            //3. Expression Bodied properties continued
            Console.WriteLine(GetHating("Megatron", "Optimus"));

            //4. Null-Conditional Operator
            //also available for event, such as "OnChanged?.Invoke(sender, args);"
            Dictionary<string, string> dic = GetDic("Shingen", "Kenshin");
            if(dic["kill"]?.GetType() == typeof(String) && dic["kill"]?.Length > 0)
            {
                Console.WriteLine(dic["kill"]);
            }

            //5. nameof operator
            //refletion machanisum, when the name of an object changed, hard-coding of its name may be missed
            //so nameof operator can help automatically get name of the object to avoid problem of hard-coding
            Console.WriteLine($"name of {nameof(dic)} is {nameof(dic)}");

            //6. exception filter & await in try..catch...finally continued
            DemoException();

            /**********************************/
            Console.WriteLine("This is the End!");
            Console.ReadKey();
        }
    }
}