IsNullOrEmpty for IEnumerable
This is not extremely relevant, but String.IsNullOrEmpty() has become a very popular time saver, and I think the same concept should be applicable to arrays and collections.
I found on Microsoft Connect that someone already added a suggestion to add IsNullOrEmpty to arrays on 2005.
This is not a big discovery, but I have been playing with extension methods in Orcas and they are so nice!
What if I define this?
public static class IEnumerableExtensions
public static bool IsNullOrEmpty(this System.Collections.IEnumerable source)
if (source == null)
Once you import the appropriate namespaces, all these things are possible:
string a = null;
var b = new Dictionary();
MemberInfo d = MethodInfo.GetCurrentMethod().DeclaringType.GetMembers();
var g = from f in d
where f.MemberType == MemberTypes.NestedType
I would like to see something like this included in System.Linq.Enumerable static class. Then it would be available to everyone, by default.
Update: I added a more complete entry as a suggestion on Microsoft Connect.
Update 2: At the Connect site, Mads teaches me why he thinks IsNullOrEmpty as an extension method is really a very bad idea. Basically, using the variable.Method invocation syntax on a method that is meant to work when the variable is null, it is very inconsistent with the instance method invocation semantics one usually gives to this syntax in languages like C# and VB.
I still think that the method, probably defined as a static method, would be nice to have on Enumerable (because it is already a well-known place to find methods that apply to the IEnumerable interface). Also, I think there is some void in the definition of extension methods. Its designers think that calling them on null instances should generally throw an exception, so why do I need to check for the parameter and throw the exception myself?