DateTime to simple string descriptions like Today, Tomorrow, Someday, etc.

DateTimeEx.cs

// Extended DateTime constants and strinify
class DateTimeEx
{
  public static DateTime NextYear { get { return DateTime.Today.AddDays(-DateTime.Today.DayOfYear + 1).AddYears(1); } }
  public static DateTime NextMonth { get { return DateTime.Today.AddDays(-DateTime.Today.Day + 1).AddMonths(1); } }
  public static DateTime NextWeek { get { return DateTime.Today.AddDays(7 - (DateTime.Today.DayOfWeek - CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek)); } }
  public static DateTime Tomorrow { get { return DateTime.Today.AddDays(1); } }
  public static DateTime Now { get { return DateTime.Now; } }
  public static DateTime Today { get { return DateTime.Today; } }
  public static DateTime Yesterday { get { return DateTime.Today.AddDays(-1); } }
  public static DateTime Monday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Monday)); } }
  public static DateTime Tuesday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Tuesday)); } }
  public static DateTime Wednesday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Wednesday)); } }
  public static DateTime Thursday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Thursday)); } }
  public static DateTime Friday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Friday)); } }
  public static DateTime Saturday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Saturday)); } }
  public static DateTime Sunday { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - DayOfWeek.Sunday)); } }
  public static DateTime ThisWeek { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek)); } }
  public static DateTime LastWeek { get { return DateTime.Today.AddDays(-(DateTime.Today.DayOfWeek - CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek) - 7); } }
  public static DateTime ThisMonth { get { return DateTime.Today.AddDays(-DateTime.Today.Day + 1); } }
  public static DateTime LastMonth { get { return DateTime.Today.AddDays(-DateTime.Today.Day + 1).AddMonths(-1); } }
  public static DateTime ThisYear { get { return DateTime.Today.AddDays(-DateTime.Today.DayOfYear + 1); } }
  public static DateTime LastYear { get { return DateTime.Today.AddDays(-DateTime.Today.DayOfYear + 1).AddYears(-1); } }
 
  private static List<Tuple<DateTime, string>> DefaultMapping { get; set; }
 
  static DateTimeEx()
  {
    DefaultMapping = new List<Tuple<DateTime, string>>();
    DefaultMapping.Add(new Tuple<DateTime, string>(NextYear.AddYears(1), "Someday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(NextYear, "Next Year"));
    DefaultMapping.Add(new Tuple<DateTime, string>(NextMonth, "NextMonth"));
    DefaultMapping.Add(new Tuple<DateTime, string>(NextWeek, "NextWeek"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Tomorrow, "Tomorrow"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Today, "Today"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Yesterday, "Yesterday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Monday, "Monday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Tuesday, "Tuesday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Wednesday, "Wednesday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Thursday, "Thursday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Friday, "Friday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Saturday, "Saturday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(Sunday, "Sunday"));
    DefaultMapping.Add(new Tuple<DateTime, string>(ThisWeek, "This Week"));
    DefaultMapping.Add(new Tuple<DateTime, string>(ThisMonth, "This Month"));
    DefaultMapping.Add(new Tuple<DateTime, string>(LastMonth, "Last Month"));
    DefaultMapping.Add(new Tuple<DateTime, string>(ThisYear, "This Year"));
    DefaultMapping.Add(new Tuple<DateTime, string>(LastYear, "Last Year"));
  }
 
  public static string ToString(DateTime dateTime, List<Tuple<DateTime, string>> mapping)
  {
    foreach (Tuple<DateTime, string> pair in mapping)
    {
      if (dateTime >= pair.Item1)
      {
        return pair.Item2;
      }
    }
 
    return null;
  }
 
  public static string ToString(DateTime dateTime)
  {
    return ToString(dateTime, DefaultMapping);
  }
}