using System;

using System.Collections.Generic;

using System.Linq;

​

public static class ListExtensions {

    public static bool IsNullOrEmpty<T>(this IEnumerable<T> enumerable)

        => enumerable == null ? true : !enumerable.Any();

}

public class Program

{

    public static void Main()

    {

        Console.WriteLine("-----------------------\nArrays\n");

        int[] nullArray = null;

        var emptyArray = new int[0];

        var anAarray = new int[]{1,2};

        Console.WriteLine($"IsNullOrEmpty(nullArray):  {ListExtensions.IsNullOrEmpty(nullArray)}");

        Console.WriteLine($"IsNullOrEmpty(emptyArray): {ListExtensions.IsNullOrEmpty(emptyArray)}");

        Console.WriteLine($"IsNullOrEmpty(anAarray):   {ListExtensions.IsNullOrEmpty(anAarray)}");

​

        Console.WriteLine("-----------------------\nLists\n");

        List<int> nullList = null;

        List<int> emptyList = new List<int>();

        List<int> aList = new List<int>() {1,2,3};

        Console.WriteLine($"IsNullOrEmpty(nullList):  {ListExtensions.IsNullOrEmpty(nullList)}");

        Console.WriteLine($"IsNullOrEmpty(emptyList): {ListExtensions.IsNullOrEmpty(emptyList)}");

        Console.WriteLine($"IsNullOrEmpty(aList):     {ListExtensions.IsNullOrEmpty(aList)}");

        Console.WriteLine("-----------------------\nDictionaries\n");

        Dictionary<int, int> nullDict = null;

        Dictionary<int, int> emptyDict = new Dictionary<int, int>();

        Dictionary<int, int> aDict = new Dictionary<int, int>() {{1,1}};

        Console.WriteLine($"IsNullOrEmpty(nullDict):  {ListExtensions.IsNullOrEmpty(nullDict)}");

        Console.WriteLine($"IsNullOrEmpty(emptyDict): {ListExtensions.IsNullOrEmpty(emptyDict)}");

        Console.WriteLine($"IsNullOrEmpty(aDict):     {ListExtensions.IsNullOrEmpty(aDict)}");

​

    }

}