Linq to SQL order by Distinct(Linq to SQL order by with Distinct)

 我的环境：VS 2013 Express中的ASP.net和C＃。 
 
 我已经通过许多类似的SO文章试图解决这个问题。 我是Linq to SQL查询和c＃的业余爱好者。 
 
 我正在尝试使用Linq to SQL从列中获取前5个最新的不同值，然后将它们添加到列表中。 我的应用程序是使用c＃的asp.net和用于数据抽象的.dbml文件。 
 
 我尝试了很多不同的方法。 我要么得到非明确但排序的列表，要么我得到一个明确的未排序列表。 到目前为止我的内容如下 
 
var Top5MFG = (from mfg in db.orders 
           where mfg.manufacturer.Length > 0 && mfg.customerid == "blahblahblahblahblah"<br />
           select new { 
              manufacturer = mfg.manufacturer,
              date = mfg.date_created 
                       })
        .Distinct()
        .OrderByDescending(s => s.date);
 
 我认为我的“Distinct”正在查看“ID”列，也许我需要告诉它我希望它看看“制造商”专栏，但我还没有弄清楚如何/如果它可以做那。 
 
 我可以通过使用storedproc轻松地完成这项工作，但是如果可能的话，我真的想直接使用c＃代码。 这是我发给SO的第一篇文章，我希望我能把它正确地放在一起。 任何帮助非常感谢。 
 
 谢谢 

My Environment: ASP.net and C# in VS 2013 Express.
 
I have been through many similar SO articles trying to work this out. I am amateur with Linq to SQL queries and c# in general.
 
I'm trying to use Linq to SQL to get the top 5 most recent distinct values from a column, then add them to a list. My application is asp.net using c# and a .dbml file for data abstraction.
 
I've tried it many different ways. I either get non-distinct yet sorted list, or I get a distinct unsorted list. What I have so far is below
 
var Top5MFG = (from mfg in db.orders 
           where mfg.manufacturer.Length > 0 && mfg.customerid == "blahblahblahblahblah"<br />
           select new { 
              manufacturer = mfg.manufacturer,
              date = mfg.date_created 
                       })
        .Distinct()
        .OrderByDescending(s => s.date);
 
I'm thinking my "Distinct" is looking at the "ID" column, and perhaps I need to tell it I want it to look at the "manufacturer" column, but I haven't worked out how / if it's possible to do that.
 
I could do this with ease by using a storedproc, but I'm really trying to do it with c# code directly if possible. This is my first post to SO, I hope I have put it together properly. Any help much appreciated.
 
Thanks

原文：https://stackoverflow.com/questions/26068277