C#获取本周五日期字符串

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Demo
{
    class Program
    {
        static void Main(string[] args)
        {
            string FriStr = GetDateOfDayInWeek(DateTime.Now, DayOfWeek.Friday);
            Console.WriteLine(FriStr);
            Console.ReadKey();
        }

        static string GetDateOfDayInWeek(DateTime dt, DayOfWeek dw)
        {
            DateTime date = dt.AddDays(dw - dt.DayOfWeek);
            //具体显示格式参见:https://msdn.microsoft.com/zh-cn/library/8tfzyc64.aspx
            return date.ToString("dd MMMM yyyy", DateTimeFormatInfo.InvariantInfo);
        }
    }
}

更多日期显示格式参照：http://www.cnblogs.com/ATree/archive/2010/06/06/CSharp-DateTime-Tostring-LongDatePattern.html