'How to filter a list based on another list using Linq?

I have these two lists, one a list of Venue Objects, one a list of BlockedVenues objects.

I need to filter each item in the listOfAllVenues so that it doesn't contain any venue that is blocked 

     IQueryable<Venue> listOfAllVenues = MyDB.Venues;
     IQueryable<BlockedVenue> listOfBlockedVenues = Mydb.BlockedVenue;
     //I need something to accomplish this please
     // var listOfAllVenues_WithoutBlocked_Venues = 
                           ( Select All venues from listOfAllVenues
                             where listOfAllVenues.ID is NOT in
                             listOfBlockedVenues.VenueID)

Please note that yes both list types are different, but listOfAllVenues has an int ID field, and listOfBlockedVenues has a VenueID int field, i need to use these two

Many Thanks

c++sharpvisual-studio-2010linq


Solution 1:[1]

As of NET 6, you can use ExceptBy.

var filtered = allVenues.ExceptBy(blockedVenues.Select(x => x.VenueID), venue => venue.ID);

This will get all venues except those whose ID is in blockedVenues.Select(x => x.VenueID)

https://docs.microsoft.com/en-us/dotnet/api/system.linq.enumerable.exceptby?view=net-6.0

Sources

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Source: Stack Overflow

Solution Source
Solution 1 Jeremy Caney

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