Forum - ado.net query

Question

I have two tables:

TOPICS
TopicId
Subject

POSTS
PostId
TopicId
AuthorId
Content
SendDate

One topic can have many posts. I need to get topics order by last reply in topic (SendDate in table Posts).

My query:

 

from x1 in Db.DataContext.Topics
//orderby ??
select x1

 

Answer 1

I can't make in that way:

 

from x1 in Db.DataContext.Topics
where x1.CategoryId == CategoryId
orderby x1.Posts.SendDate descending //here error
select x1

 

because then I have an error: Models.Posts does not contain a definition for SendDate - so what can I do ?

Answer 2

Hi green_green;

You can not reorder the collection that is attached to the topics table so what you can do is to create a result set that has the topic and also contains a list of post ordered in the way you need them.

var query = from t int DataContext.Topics
      where t.CategoryId == CategoryId
      select new
      {
      	topic = t,
      	post = t.Posts.OrderByDescending( p => p.SendDate )
      }

 

 

 

---

Fernando

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