// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002564/object-nullif

​

// @nuget: Z.ExtensionMethods

​

using System;           

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        string str = "1";

​

        // C# Extension Method: Object - NullIf

        string result1 = str.NullIf(x => x == "1"); // return null;

        string result2 = str.NullIf(x => x == "2"); // return "1";

​

        Console.WriteLine(result1);

        Console.WriteLine(result2);

    }

}