DateTime - LastDayOfWeek

A DateTime extension method that return a DateTime of the last day of week.

Try it

public static void Main()
{
    DateTime now = DateTime.Now;
	
	Console.WriteLine("Current Date    : {0}", now.ToFullDateTimeString());
	
	// C# Extension Method: DateTime - LastDayOfWeek
	DateTime lastDayOfWeek = now.LastDayOfWeek();
	
	Console.WriteLine("Last day of week: {0}", lastDayOfWeek.ToFullDateTimeString());
}

View Source 
using System;

public static partial class Extensions
{
    /// <summary>
    ///     A DateTime extension method that last day of week.
    /// </summary>
    /// <param name="this">The @this to act on.</param>
    /// <returns>A DateTime.</returns>
    public static DateTime LastDayOfWeek(this DateTime @this)
    {
        return new DateTime(@this.Year, @this.Month, @this.Day).AddDays(6 - (int) @this.DayOfWeek);
    }
}