Question

I use:

if (!ObjectCollection.Any(o => o.Property == SomeValue))
    // ...

or:

if (!IntCollection.Contains(42))
    // ...

to determine if a collection does not have a particular element, but some people miss the ! negation and misinterpret.

Is there another way to determine that a collection does not contain a particular element that doesn’t use the negation operator? I prefer to stick to dot notation instead of query expression, but maybe a query expression is more readable to someone who misses the bang.

Answer 1

There’s nothing in standard LINQ, but if you really don’t like using ! (which is the approach I’d recommend) you could always write your own extension methods:

public static bool DoesNotContain<T>(this IEnumerable<T> source, T item)
{
    return !source.Contains(item);
}


public static bool None<T>(this IEnumerable<T> source, Func<T, bool> predicate)
{
    return !source.Any(predicate);
}

(You can use these for things like LINQ to SQL as well if you’re just using them as the final call – you wouldn’t be able to use them in nested queries though, as the query translator wouldn’t understand them.)