Ways of handling null collections and AddRange

gistfile1.cs

// a)
if (items != null)
  collection.AddRange(items)

// b)
collection.AddRange(items ?? new Foo[0])

If no other option, I'd take a), as it seems awkward to add an empty array just for succintness of code. Optionally a "TryAdd" extension method on IList would be in order :)

if(!Object.ReferenceEquals(items, null)
  collection.AddRange(items);

:P

I agree with @flq

Oh, and with the serious side, I'd be with @flq - I'd not bother with adding an empty array, and I disagree with Hadi - I make it a goal to avoid adding braces to my code. Forces the creation of methods a lot of the time and therefore increases readability.

@robashton I'm trying to make the code more succinct, not less.

if(items == null)
items = new Foo[0];

collection.AddRange(items);

Or even:
items = items ?? new Foo[0];
collection.AddRange(items);

@ashic still completely pointless

I agree with @flq.

I know, I know, I know!!

public static class IEnumerableExtensions {
    public static void AddTo<T>(this IEnumerable<T> self, ICollection<T> destination) {
        if(self != null) destination.AddRange(self);
    }
}

and

items.AddTo(collection);

What do I win?

what...nobody for good old
if(null != items) collection.AddRange(items);
?

@ashic Same difference there really, except yours is more verbose than both :)

I personally prefer B, mainly because it's got a bit less indentation and the AddRange is a little more focal; that being said, having the new array is a bit of a shame. I could use Enumerable.Empty() which will only allocate a new array the first time around, but that just isn't as neat and tidy.

@robashton I think that should be collection.NullSafeAddRange(items)?

Just use Rob's extension method...nice and clean...and what I use on "real" projects ;)

@jagregory collection.CheckIfThisIsNullAndIfThisIsNotAddTheItemsInTheCollectionToMe(items); [Something Neil might write ;) ]

@jagregory I don't like it, not enough job security

Small correction to @robashton's extension because ICollection doesn't have AddRange:

using System.Collections.Generic;

public static class IEnumerableExtensions
{
    public static void AddTo<T>(this IEnumerable<T> self, List<T> destination)
    {
        if(self != null) destination.AddRange(self);
    }
}

@leniel How do you call this extension method on self if self is null? It seems like it would cause some exception))