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c#entity-frameworklinq
Trevor Daniel
Trevor Daniel

Reputation: 3974

Linq Include from List<string>

Is it possible to specify "Includes" from a List please?

I have a list of possible sub tables to be included in:

List<string> includedTables

My current database call looks like this:

return db.SA_Items
       .Where(x => x.LastUpdated > lastUpdated)
       .Where(x => x.Active == true)
       .OrderBy(x => x.ItemID)
       .Skip(offset)
       .Take(limit)
       .ToList();

I would to somehow to a foreach string in the List and add a .Include(....) to the database call...

Say, for example, if there were 2 strings in the list the code would be equivalent to this:

return db.SA_Items
       .Include("first string in the list")
       .Include("second string in the list")
       .Where(x => x.LastUpdated > lastUpdated)
       .Where(x => x.Active == true)
       .OrderBy(x => x.ItemID)
       .Skip(offset)
       .Take(limit)
       .ToList();

It's also possible that the List might be null.

Is it possible to do this dynamically somehow?

Can anyone give me any pointers please?

Upvotes: 3

Views: 3697

Answers (3)

ocuenca
ocuenca

Reputation: 39386

Sure, you can build your query in several steps:

IQueryable<SA_Item> query=db.SA_Items;
if(includedTables!=null)
   query = includedTables.Aggregate(query, (current, include) => current.Include(include));

query=query.Where(x => x.LastUpdated > lastUpdated)
           .Where(x => x.Active == true)
           .OrderBy(x => x.ItemID)
           .Skip(offset)
           .Take(limit);
return query.ToList();// Materialize your query

Upvotes: 4

Matthew Thurston
Matthew Thurston

Reputation: 760

you can do it with concat.

return db.SA_Items
       .Concat(new string[] {"first string in the list", "second string in the list"})
       .Where(x => x.LastUpdated > lastUpdated)
       .Where(x => x.Active == true)
       .OrderBy(x => x.ItemID)
       .Skip(offset)
       .Take(limit)
       .ToList();

Upvotes: 0

Monofuse
Monofuse

Reputation: 827

You could do a similar thing which is happening in the following stackoverflow link, but replace the int index which has been added with your strings:

LINQ: Add RowNumber Column

Upvotes: 0

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