あなたが見た最も恐ろしいLINQ機能は何ですか？

私は個人的なプロジェクトに取り組んでいましたが、Outlookからアイテムを抽出し、WCFで "RESTful"なデザインでホストする簡単なサービスが必要でした。その過程で、私はこのやや野生のクラスを考え出しました。あなたが見た最も恐ろしいLINQ機能は何ですか？

他の恐ろしいlinqコードは見ましたか？

public IQueryable<_AppointmentItem> GetAppointments(DateTime date) 
{ 
    var dayFlag = (OlDaysOfWeek)(int)Math.Pow(2, (int)date.DayOfWeek); 
    return 
     OlDefaultFolders.olFolderCalendar.GetItems<_AppointmentItem>() 
     .Select(a => new 
     { 
      Appointment = a, 
      RecurrencePattern = a.IsRecurring ? 
           a.GetRecurrencePattern() : null 
     }) 
     .Where(a => 
      a.Appointment.Start.Date <= date && 
      (
       (a.RecurrencePattern == null && 
       a.Appointment.End.Date >= date) || 
       (
        a.RecurrencePattern != null && 
        (
         (a.RecurrencePattern.DayOfMonth == 0 || 
         a.RecurrencePattern.DayOfMonth == date.Day) && 
         (a.RecurrencePattern.DayOfWeekMask == 0 || 
         ((a.RecurrencePattern.DayOfWeekMask & 
          dayFlag) != 0)) && 
         (a.RecurrencePattern.MonthOfYear == 0 || 
          a.RecurrencePattern.MonthOfYear == date.Month) 
        ) 
       ) 
      ) 
     ) 
     .Select(a => a.Appointment); 
} 

[OperationContract()] 
[WebGet(
    UriTemplate = "/appointments/{year}/{month}/{day}", 
    RequestFormat = WebMessageFormat.Xml, 
    ResponseFormat = WebMessageFormat.Xml, 
    BodyStyle = WebMessageBodyStyle.Bare 
    )] 
[ContentType("text/xml")] 
public XElement ListAppointments(string year, string month, string day) 
{ 
    try 
    { 
     int iYear, iMonth, iDay; 
     int.TryParse(year, out iYear); 
     int.TryParse(month, out iMonth); 
     int.TryParse(day, out iDay); 

     if (iYear == 0) iYear = DateTime.Now.Year; 
     if (iMonth == 0) iMonth = DateTime.Now.Month; 
     if (iDay == 0) iDay = DateTime.Now.Day; 

     var now = new DateTime(iYear, iMonth, iDay).Date; // DateTime.Now; 
     return GetAppointments(now).ToXml(); 
    } 
    catch (System.Exception ex) 
    { 
     return new XElement("exception", ex.ToString()); 
    } 
} 


using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Xml.Linq; 
using Microsoft.Office.Interop.Outlook; 

namespace WhitedUS.ServiceModel.Office.Linq 
{ 
    public static class OutlookUtilities 
    { 
     public static IQueryable<T> GetItems<T>(
      this OlDefaultFolders defaultFolderType) 
     { 
      return 
       new ApplicationClass() 
       .Session 
       .GetDefaultFolder(defaultFolderType) 
       .Items 
       .OfType<T>() 
       .AsQueryable(); 
     } 

     public static XElement ToXml<T>(this IEnumerable<T> input) 
     { 
      if (input == null) 
       return null; 

      Type typ = typeof(T); 
      var root = XName.Get(typ.Name.Trim('_')); 

      return new XElement(root, 
       input 
       .Select(x => x.ToXml<T>()) 
       .Where(x => x != null) 
       ); 
     } 

     public static XElement ToXml<T>(this object input) 
     { 
      if (input == null) 
       return null; 

      Type typ = typeof(T); 
      var root = XName.Get(typ.Name.Trim('_')); 

      return new XElement(root, 
       typ.GetProperties() 
       .Where(p => p.PropertyType.IsValueType || 
         p.PropertyType == typeof(string)) 
       .Select(p => new { Prop = p, Getter = p.GetGetMethod() }) 
       .Where(p => p.Getter != null) 
       .Select(p => new { Prop = p.Prop, Getter = p.Getter, 
            Params = p.Getter.GetParameters() }) 
       .Where(p => (p.Params == null || p.Params.Count() <= 0)) 
       .Select(p => new { Name = p.Prop.Name, 
            Value = p.Getter.Invoke(input, null) }) 
       .Where(p => p.Value != null) 
       .Select(p => new XAttribute(XName.Get(p.Name), p.Value)) 
       ); 
     } 
    } 
}

も参照してください：What is the worst abuse you’ve seen of LINQ syntax?

出典

2009-05-11 Matthew Whited