Filter IEnumerable against IEnumerable

Question

I have an object Style with a property StockNumber. I would like to filter a list of all Db.Styles against an IEnumerable

Answer 1

public IEnumerable<Style> LoadListOfStyles(List<string> stockNumbers)
{
    return db.Styles.Where(s => stockNumbers.Contains(s.StockNumber));
}

Answer 2

Consider a Where clause.

public IEnumerable<Style> LoadListOfStyles(IEnumerable<string> stockNumbers)
{
    return Db.Styles.Where(style => !stockNumbers.Contains(style.StockNumber));
}

Answer 3

return db.Styles.Where(style => stockNumbers.Any(sn => sn == style.StockNumber));

Answer 4

You can think of Intersect as effectively a Join where the keys of each object are always "themselves". Here you want to perform a join where the key isn't always "itself", so you use a Join (or, if you need to remove duplicates, a GroupJoin).

var query = from style in Db.Styles
    join number in stockNumbers
    on style.StockNumber equals number
    into numbers
    where numbers.Any()
    select style;