DateTime dt = DateTime.Now;
DateTime startWeek = dt.AddDays(1 - Convert.ToInt32(dt.DayOfWeek.ToString("d")));
var count =0;//自己定义的变量 循环
System.Globalization.CultureInfo.CurrentCulture.DateTimeFormat.GetDayName(startWeek.AddDays(count).DayOfWeek)//获取这个日期星期几
原文：http://www.cnblogs.com/yhyl/p/7700145.html