Why is there no Sort for IList<T>?!?! (edited)

Question

I was pretty surprised when I discovered that there is no direct way to sort or perform a binary search on an IList< T >. Just like there are static methods to sort and perform a binary search on an Array, I think that it would be awfully helpful to have similar static methods that take an IList< T >.

Currently:

class Array
{
    static Sort<T>(T[] array);
    static int BinarySearch<T>(T[] array, T item);
}

I wish they would add:

class List
{
    static Sort<T>(IList<T> list);
    static int BinarySearch<T>(IList<T> list, T item);
}

I glanced at the .NET Framework 4.0 Beta SDK and there still doesn't appear to be a solution to this problem.

I know that I could work around this by creating an extension method that checks if it is a List< T > and then sort/search using the List< T > instance; however, if it is not an instance of a List< T >, then I have to perform a copy (which stinks for very large lists). I know I could do all of this, but why? Is there some reason they have intentionally omitted this feature?

To try to get this in the .NET 4.0 Framework, I have created a suggestion via Microsoft's Connect program. If you are frustrated like me about this issue, vote on it and maybe it will get added.

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=474201

Answer 1

LINQ has a OrderBy method that works on all IEnumerable<T>, including IList<T>. You can accomplish the same thing using OrderBy.

// Order a list of addresses:
IList<string> list = ...
var orderedList = list.OrderBy(input => input);

Answer 2

I think there's a pretty good case for not including a sort method for IList<T>. First, it would create added complexity for those that want to implement an IList and second it would make it harder for the IList interface to conform to the Interface Segregation Principle.

Generally what I do if I need to perform a sort on an IList<T> is create a new List<T> and pass in the IList<T> as a parameter

so for example:

        public IList<Address> SortAddresses(IList<Address> addresses)
        {
            var sortedAddresses = new List<Address>(addresses);
            sortedAddresses.Sort();
            return sortedAddresses;
        }