// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002255/datetime-firstdayofweek

​

// @nuget: Z.ExtensionMethods

​

using System;

using System.Globalization;

​

public class Program

{

    public static void Main()

    {

        DateTime date = DateTime.Now;

        Console.WriteLine("Original DateTime                    : {0}", date.ToFullDateTimeString());

​

        // C# Extension Method: DateTime - FirstDayOfWeek

        DateTime endOfDay = date.FirstDayOfWeek();

        Console.WriteLine("DateTime after calling FirstDayOfWeek: {0}", endOfDay.ToFullDateTimeString());

    }

}