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c#linqentity-framework
Kalanamith
Kalanamith

Reputation: 20648

LinQ Error linq joint type inference failed to call 'join' error

I'm quite new to entity framework and I'm trying to use the join clause on two entities as follows. 

var alertlist = from elogAlert  in yangkeeDBEntity.Yang_Kee_Logistics_Pte_Ltd_ELog_Tablet_Alert
                        where elogAlert.No_ != null
                        join elogAlertDetail in  yangkeeDBEntity. Yang_Kee_Logistics_Pte_Ltd_ELog_Tablet_Alert_Details
                        on elogAlert.No_ == elogAlertDetail.AlertID



                        where elogalertdetail.employee_id == driverid
                        select new
                        {
                            elogalertdetail.employee_id,
                            elogalertdetail.alert_id,
                            elogalertdetail.no_,
                            elogalertdetail.status,
                            elogalertdetail.created_by,
                            elogalertdetail.date_created,



                        };

Hi from the above code I'm getting two errors saying 

'Error  1   The name 'elogAlertDetail' is not in scope on the left side of 'equals'.  Consider swapping the expressions on either side of 'equals'.' and 'linq joint type inference failed to call 'join' error  '

Currently the two tables does not have any data. Ill be happy if anyone can help me with this situation

Upvotes: 1

Views: 2414

Answers (2)

undefined
undefined

Reputation: 34248

The error you have relates to the order of arguments around the equals operand on join.

The joined table MUST be the RHS of the equals, and the LHS must be in the row you are joining to.

In this instance yangkeeDBEntity is not in the elogAlert row

CF the example in MSDN

from c in categories 
        join p in products on c equals p.Category into ps 
        from p in ps 
        select new { Category = c, p.ProductName };

c is in the row you are joining from, p.category is on the table you are joining to

in addition you also need to use the word equals not == as mentioned above

Upvotes: 1

Jens Kloster
Jens Kloster

Reputation: 11277

you cant use == when joining with Linq. You need to use equals.

Note that it is not the method .Equals(..) but the keyword

from elogAlert  in yangkeeDBEntity.Yang_Kee_Logistics_Pte_Ltd_ELog_Tablet_Alert
join elogAlertDetail in  yangkeeDBEntity.Yang_Kee_Logistics_Pte_Ltd_ELog_Tablet_Alert_Details

on elogAlert.No_ equals elogAlertDetail.AlertID //this line has equals instead of ==

                        where elogAlert.No_ != null
                        where elogalertdetail.employee_id == driverid
                        select new
                        {
                            elogalertdetail.employee_id,
                            elogalertdetail.alert_id,
                            elogalertdetail.no_,
                            elogalertdetail.status,
                            elogalertdetail.created_by,
                            elogalertdetail.date_created,
                        };

Look at the documentaion on Linq join

Upvotes: 4

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