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up vote 1 down vote favorite

I have the following statement in LINQ:

var eventsWithTag = (from occurence in occurrences1
                     join eventTag in serviceContext.CreateQuery("adx_eventtag_event")
                         on occurence.Event.GetAttributeValue<Guid>("adx_eventid") equals eventTag.GetAttributeValue<Guid>("adx_eventid")
                     join tag in serviceContext.CreateQuery("adx_eventtag")
                         on eventTag.GetAttributeValue<Guid>("adx_eventtagid") equals tag.GetAttributeValue<Guid>("adx_eventtagid")
                     where tag.GetAttributeValue<string>("adx_name") == "scotland"
                     select occurence).OrderBy(x => x.Start);

This works fine with the fixed string search of "Scotland" in this instance. However I need to replace that to reflect the current page topic. So essentially I need to replace

== "scotland"

with

== getBranch()

where getBranch returns the relevant branch name as a string.

This would lead me to try

eventsWithTag = (from occurence in occurrences1
join eventTag in serviceContext.CreateQuery("adx_eventtag_event") on occurence.Event.GetAttributeValue<Guid>("adx_eventid") equals eventTag.GetAttributeValue<Guid>("adx_eventid")
join tag in serviceContext.CreateQuery("adx_eventtag") on eventTag.GetAttributeValue<Guid>("adx_eventtagid") equals tag.GetAttributeValue<Guid>("adx_eventtagid")
where tag.GetAttributeValue<string>("adx_name") == getBranch()
select occurence).OrderBy(x => x.Start);

But this doesnt work, and from what little I know of LINQ it is because you cant use variables in this way.

So my question is: How can I use the LINQ query above with a dynamic value for the branch.

Please note: I have seen other posts about this but I evidently don't have the LINQ knowledge to transfer them to my specific needs. Just yet!

share|improve this question
1  
Does it give you an error? or does it just return the wrong results? –  p.s.w.g Apr 25 '13 at 18:56
    
No results. However I know the result of getBranch() is correct. –  Phill Healey Apr 25 '13 at 18:58

2 Answers 2

up vote 2 down vote accepted

Everything looks right so I'd double check your getBranch()...

if this works:

var branch = "scotland";
eventsWithTag = 
    (from occurence in occurrences1
     join eventTag in serviceContext.CreateQuery("adx_eventtag_event") on occurence.Event.GetAttributeValue<Guid>("adx_eventid") equals eventTag.GetAttributeValue<Guid>("adx_eventid")
     join tag in serviceContext.CreateQuery("adx_eventtag") on eventTag.GetAttributeValue<Guid>("adx_eventtagid") equals tag.GetAttributeValue<Guid>("adx_eventtagid")
     where tag.GetAttributeValue<string>("adx_name") == branch 
     select occurence)
    .OrderBy(x => x.Start);

Then p.s.w.g's answer should work, and your issue lies with getBranch returning a value that doesn't match any records...

On a slightly different matter, I'm slightly confused as to why you need to get the actual attributes in your equals statement, because according to this, it should work fine like this:

var branch = "scotland";
eventsWithTag = 
    (from occurence in occurrences1
     join eventTag in serviceContext.CreateQuery("adx_eventtag_event") on occurence.Event["adx_eventid"] equals eventTag["adx_eventid"]
     join tag in serviceContext.CreateQuery("adx_eventtag") on eventTag["adx_eventtagid"] equals tag["adx_eventtagid"]
     where tag["adx_name"] == branch 
     select occurence)
    .OrderBy(x => x.Start);
share|improve this answer
    
This linq excluding the orderby bit were written for me by the guys who make the adx Portals for Dynamics eg adxstudio.com –  Phill Healey Apr 25 '13 at 19:09
1  
@PhillHealey I agree with Daryl, if var branch = "scotland" works but var branch = getBranch() doesn't, the error has to be in getBranch(). –  p.s.w.g Apr 25 '13 at 19:29
    
Yeah it looks like I wasted hours of my day on a simple capilisation of the first letter scenario! Damn this job! ;-) –  Phill Healey Apr 25 '13 at 19:41
    
If you started using the early-bound classes that would never happen. :) Btw, I encourage everyone if they aren't using early-bound classes to generate classes with strings for the field names: replacing CreateQuery("adx_eventtag_event") with CreateQuery(adx_eventtag_event.EntityLogicalName) and tag["adx_name"] with tag[adx_eventtag.fields.adx_name] - not as good as early bound but better than hard-coding the strings all over the code. –  Nicknow Apr 25 '13 at 21:31
    
@Nicknow How so? –  Phill Healey Apr 28 '13 at 12:09
up vote 2 down vote

You can just make the call beforehand:

var branch = getBranch();
eventsWithTag = 
    (from occurence in occurrences1
     join eventTag in serviceContext.CreateQuery("adx_eventtag_event") on occurence.Event.GetAttributeValue<Guid>("adx_eventid") equals eventTag.GetAttributeValue<Guid>("adx_eventid")
     join tag in serviceContext.CreateQuery("adx_eventtag") on eventTag.GetAttributeValue<Guid>("adx_eventtagid") equals tag.GetAttributeValue<Guid>("adx_eventtagid")
     where tag.GetAttributeValue<string>("adx_name") == branch 
     select occurence)
    .OrderBy(x => x.Start);
share|improve this answer
    
Really? That simple? Doh!!! Ill give it a try. –  Phill Healey Apr 25 '13 at 18:43

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