实体框架/ linq查询问题

Question

So I am trying to work around the lack of stored procedure support in my silverlight reporting application and Im having a bit of trouble with my linq.

I have a stored procedure that looks like this:

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:  Some Dev Guy
-- Create date: 11/02/10
-- =============================================
Alter PROCEDURE spGetTopReferers
 @p_sitekey SmallInt, 
 @p_startDate SmallDateTime, 
 @p_endDate SmallDateTime
AS
BEGIN

 SET NOCOUNT ON;  

 SELECT 
  TOP 10 
   SUM(DaySummaryReferrers.Visits) AS Visits, 
   SUM(DaySummaryReferrers.NewVisitors) AS 'New Visitors', 
   SUM(DaySummaryReferrers.Prospects) AS Prospects, 
   SUM(DaySummaryReferrers.Customers) AS Customers, 
   Referrers.Referrer
  FROM 
   DaySummaryReferrers 
   LEFT OUTER JOIN 
   Referrers 
   ON 
   DaySummaryReferrers.ReferrerID = Referrers.ReferrerID
  Where 
   DaySummaryReferrers.SiteKey = @p_sitekey 
   AND
   DaySummaryReferrers.Dated 
    Between 
     @p_startDate
     AND
     @p_endDate
  GROUP BY 
   Referrers.Referrer
  ORDER BY 
   Visits DESC; 
END
GO

I have created the following DomainService Class so that I may query this day using entity framework. I want to push the result of my query into my custom data structure becuase I dont have an entity that has all the information i need for my report (specifically visits and referrer)

namespace Reports.Web.Services
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using System.Linq;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;
    using System.Data;
    using System.Data.Objects;

    public class TopReferers
    {
        [Key]
        [Editable(false)]
        public int reffererID { get; set; }
        public int? Visits { get; set; }
        public int? Visitors { get; set; }
        public int? Prospects { get; set; }
        public int? Customer { get; set; }
        public String Referrer { get; set; }

    }

    [EnableClientAccess()]
    public class WebReportAggregateService : DomainService
    {
        WhosOnV5DevEntities ctx = new WhosOnV5DevEntities();

        public IQueryable<TopReferers> GetTopReferrers()
        {

            DateTime p_start = new DateTime(2010, 01, 01);
            DateTime p_end = new DateTime(2010, 11, 01);

            ObjectSet<DaySummaryReferrer> myReferrers = ctx.DaySummaryReferrers;
            ObjectSet<Referrer> myReferrerNames = ctx.Referrers;


            IQueryable<TopReferers> x = from referrer in myReferrers.Take(10)
                                         join referrerName in myReferrerNames
                                         on referrer.ReferrerID
                                         equals referrerName.ReferrerID
                                         where
                                         referrer.SiteKey == 74
                                         &&
                                         referrer.Dated >= p_start
                                         &&
                                         referrer.Dated <= p_end
                                         group referrer by referrerName.Referrer1 into g
                                         select new TopReferers { Visits = g.Key.Visits, Customer = g.Key.Customers, Prospects = g.Key.Prospects, Visitors = g.Key.NewVisitors, Referrer = g.Key.Referrer, reffererID = g.Key.ReferrerID };


            return x;
        }

    }
}

This is where I am getting errors:

select new TopReferers { Visits = g.Key.Visits, Customer = g.Key.Customers, Prospects = g.Key.Prospects, Visitors = g.Key.NewVisitors, Referrer = g.Key.Referrer, reffererID = g.Key.ReferrerID };

Errors:

Error   2   'string' does not contain a definition for 'Customers' and no extension method 'Customers' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?) C:\Users\User\documents\visual studio 2010\Projects\Reports\Reports.Web\Services\WebReportAggregateService.cs   53  108 Reports.Web

I get this error for Visits, Custom, Prospects, Visitors, Referrer, and ReferrerID.

Any Help would be greatly appreciated =D

Answer 1

In your class properties you have Customer singular and in your LINQ you have Customers plural.

public class TopReferers
{
    [Key]
    [Editable(false)]
    public int reffererID { get; set; }
    public int? Visits { get; set; }
    public int? Visitors { get; set; }
    public int? Prospects { get; set; }
    public int? **Customer** { get; set; }
    public String Referrer { get; set; }

}

Answer 2

What is the type of Referrer.Referrer1 ? From the errors, it sounds like your group key is a string .

I think what you want to do is group by a composite key:

group referrer by new { ID = referrerName.ReferrerID, Name = referrerName.Referrer1 }

and then select this:

select new TopReferers { referrerID = g.Key.ID,
                         Visits = g.Sum(x => x.Visits),
                         Visitors = g.Sum(x => x.NewVisitors),
                         Prospects = g.Sum(x => x.Prospects),
                         Customer = g.Sum(x => x.Customers),
                         Referrer = g.Key.Name }