CODEWITHSUNDEEP
linqentity-framework
sisdog
sisdog

Reputation: 2719

LINQ Statement Doesn't Compile

This statement won't compile:

query = from g in context.GridViews 
   join f in context.GridViewFavorites on g.ID equals f.GridViewID into gf
   where g.GridTypeID == id && ( g.IsShared == true || g.RepID == me.clsRep.OID) 
   && f.RepID == me.clsRep.OID
   select g;

The compiler error is this (and it's underlining the last part of the where clause:

The name 'f' does not exist in the current context

It's logical SQL counterpart would be:

declare @RepID int
declare @GridTypeID int
select @RepID=15, @GridTypeID=5

select g.*,f.*
from
   GridViews g
   left outer join GridViewFavorites f on f.GridViewID = g.ID
where
   g.GridTypeID = @GridTypeID and (g.IsShared = 1 or g.RepID == @RepID) 
   and f.RepID == @RepID

NOTE: per @hdv 's good catch the SQL sample should actually be:

select g.*,f.*
from
   GridView g
   left outer join GridViewFavorite f on f.GridViewID = g.ID and f.RepID = @RepID
where
   g.GridTypeID = @GridTypeID and (g.IsShared = 1 or g.RepID = @RepID)

Upvotes: 0

Views: 127

Answers (3)

driis
driis

Reputation: 164291

The where clause acts on the joined result, so the f variable is not in scope.

Upvotes: 0

usr
usr

Reputation: 171178

The left-join pattern for LINQ goes like this:

join f in context.GridViewFavorites on g.ID equals f.GridViewID into gf
from f in gf.DefaultIfEmpty() //missing

More information is available on Stack Overflow and Google.

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1500525

It's the "into" part of your join - once you've joined "into" a group, the join variable (f in this case) is out of scope - you've got to use gf instead. Alternatively, given that you're not actually using gf in your query at all, maybe you should just get rid of the into gf part entirely so it's a normal join instead of a group join.

However, that won't give you a left outer join. If you want a left outer join, you might want:

query = from g in context.GridViews 
   join f in context.GridViewFavorites on g.ID equals f.GridViewID into gf
   from f2 in gf.DefaultIfEmpty()
   where g.GridTypeID == id && (g.IsShared == true || g.RepID == me.clsRep.OID) 
   && (f2 == null || f2.RepID == me.clsRep.OID)
   select g;

Upvotes: 5

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