// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002563/object-ifnotnull

​

// @nuget: Z.ExtensionMethods

​

using System;           

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var values = new List<string> { "Fizz", "Buzz" };

        List<string> valuesNull = null;

        string actionOutput1 = null;

        string actionOutput2 = null;

​

        // C# Extension Method: Object - IfNotNull

        string result1 = values.IfNotNull(x => x.First(), "FizzBuzz"); // return "Fizz";

        string result2 = valuesNull.IfNotNull(x => x.First(), "FizzBuzz"); // return "FizzBuzz";

        string result3 = valuesNull.IfNotNull(x => x.First(), () => "FizzBuzz"); // return "FizzBuzz"

​

        values.IfNotNull(x => actionOutput1 = string.Join("", values)); // = "FizzBuzz"

        valuesNull.IfNotNull(x => actionOutput2 = string.Join("", values)); // Do Nothing

​

        Console.WriteLine(result1);

        Console.WriteLine(result2);

        Console.WriteLine(result3);

​

        Console.WriteLine(actionOutput1);

        Console.WriteLine(actionOutput2);

    }

}