?
Solved

linq groupjoin using lambda with a where clause

Posted on 2013-01-13
4
Medium Priority
?
769 Views
Last Modified: 2013-11-05
I need to add a join using Lambda if I have a further parameter available that will also be used in a where clause.

This is my original linq code, it works just fine...

    var tagList =   from t in dc.Tags
    join b in dc.Businesses on t.BusinessId equals b.BusinessId
            where t.IsActive == true
            where b.IsActive == true
            orderby t.AdImage descending
            select new TagItem
            {
                    tagName = t.Name.Replace("\"", ""),
                    tagImage = tagImagePath + t.AdImage.Replace("\"", ""),
                    tagDescription = t.Description.Replace("\"", "")
            };

My problem is I'm not sure of the exact format for adding a new object [table] MemberTagLysts using Lambda and then how the where clause should be created when I have a lystId available...

This is not quite right....

            if (!string.IsNullOrEmpty(lystId))
            {
                            tagList = (IQueryable<TagItem>)tagList.GroupJoin(dc.MemberTagLysts, a => a.tagId, b => b.TagId, (a, b) => new { a, b });
            }
0
Comment
Question by:Rob Gaudet
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
4 Comments
 
LVL 42

Expert Comment

by:sedgwick
ID: 38774007
can u explain what kind of join you wish to apply with MemberTagLysts table?
0
 
LVL 42

Expert Comment

by:sedgwick
ID: 38774017
first u need to add tagId in your initial linq query:
.
.
.select new TagItem
            {
tagId = t.tagId,
                    tagName = t.Name.Replace("\"", ""),
                    tagImage = tagImagePath + t.AdImage.Replace("\"", ""),
                    tagDescription = t.Description.Replace("\"", "")
            };

Open in new window


now try run this:
   tagList = (IQueryable<TagItem>)tagList.GroupJoin(dc.MemberTagLysts, a => a.tagId, b => b.TagId, (a, b) => new { a, b });

Open in new window

0
 

Author Comment

by:Rob Gaudet
ID: 38779233
Sorry, tagid was in the initial query, I shortened the values to save space and pulled it out..

Your suggestion...

tagList = (IQueryable<TagItem>)tagList.GroupJoin(dc.MemberTagLysts, a => a.tagId, b => b.TagId, (a, b) => new { a, b });

....returned this error.

Unable to cast object of type 'System.Data.Linq.DataQuery`1[<>f__AnonymousType6`2[TagItem,System.Collections.Generic.IEnumerable`1[MemberTagLyst]]]' to type 'System.Linq.IQueryable`1[TagItem]'.
0
 
LVL 42

Accepted Solution

by:
sedgwick earned 1500 total points
ID: 38779580
just
var group = tagList.GroupJoin(dc.MemberTagLysts, a => a.tagId, b => b.TagId, (a, b) => new { a, b });

Open in new window

0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I'm trying, I really am. But I've seen so many wrong approaches involving date(time) boundaries I despair about my inability to explain it. I've seen quite a few recently that define a non-leap year as 364 days, or 366 days and the list goes on. …
Occasionally there is a need to clean table columns, especially if you have inherited legacy data. There are obviously many ways to accomplish that, including elaborate UPDATE queries with anywhere from one to numerous REPLACE functions (even within…
This is my first video review of Microsoft Bookings, I will be doing a part two with a bit more information, but wanted to get this out to you folks.
In this video, Percona Solution Engineer Rick Golba discuss how (and why) you implement high availability in a database environment. To discuss how Percona Consulting can help with your design and architecture needs for your database and infrastr…

719 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question