// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002280/datetimeoffset-notin

​

// @nuget: Z.ExtensionMethods

​

using System;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        DateTimeOffset [] values = { new DateTimeOffset(2017, 9, 1, 6, 45, 0, new TimeSpan(-7, 0, 0)),

                                     new DateTimeOffset(2017, 11, 1, 6, 45, 0, new TimeSpan(-6, 0, 0)),

                                     new DateTimeOffset(2017, 10, 1, 8, 45, 0, new TimeSpan(-5, 0, 0))};

​

        DateTimeOffset date = new DateTimeOffset(2007, 10, 1, 8, 45, 0, new TimeSpan(-5, 0, 0));

​

        // C# Extension Method: DateTimeOffset - NotIn

        if(date.NotIn(values))

        {

            Console.WriteLine("{0} doesn't exists in the list.", date);

        }

        else

        {

            Console.WriteLine("{0} exists in the list.", date);

        }

    }

}