Sorting an IList in C#

So I came across an interesting problem today. We have a WCF web service that returns an IList. Not really a big deal until I wanted to sort it.

Turns out the IList interface doesn't have a sort method built in.

I ended up using the ArrayList.Adapter(list).Sort(new MyComparer()) method to solve the problem but it just seemed a bit "ghetto" to me.

I toyed with writing an extension method, also with inheriting from IList and implementing my own Sort() method as well as casting to a List but none of these seemed overly elegant.

So my question is, does anyone have an elegant solution to sorting an IList

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How about using LINQ To Objects to sort for you?

Say you have a IList<Car> , and the car had an Engine property, I believe you could sort as follows:

from c in list
orderby c.Engine
select c;

Edit: You do need to be quick to get answers in here. As I presented a slightly different syntax to the other answers, I will leave my answer - however, the other answers presented are equally valid.

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你可以使用LINQ：

using System.Linq;

IList<Foo> list = new List<Foo>();
IEnumerable<Foo> sortedEnum = list.OrderBy(f=>f.Bar);
IList<Foo> sortedList = sortedEnum.ToList();

---

This question inspired me to write a blog post: http://blog.velir.com/index.php/2011/02/17/ilistt-sorting-a-better-way/

I think that, ideally, the .NET Framework would include a static sorting method that accepts an IList<T>, but the next best thing is to create your own extension method. It's not too hard to create a couple of methods that will allow you to sort an IList<T> as you would a List<T>. As a bonus you can overload the LINQ OrderBy extension method using the same technique, so that whether you're using List.Sort, IList.Sort, or IEnumerable.OrderBy, you can use the exact same syntax.

public static class SortExtensions
{
    //  Sorts an IList<T> in place.
    public static void Sort<T>(this IList<T> list, Comparison<T> comparison)
    {
        ArrayList.Adapter((IList)list).Sort(new ComparisonComparer<T>(comparison));
    }

    // Convenience method on IEnumerable<T> to allow passing of a
    // Comparison<T> delegate to the OrderBy method.
    public static IEnumerable<T> OrderBy<T>(this IEnumerable<T> list, Comparison<T> comparison)
    {
        return list.OrderBy(t => t, new ComparisonComparer<T>(comparison));
    }
}

// Wraps a generic Comparison<T> delegate in an IComparer to make it easy
// to use a lambda expression for methods that take an IComparer or IComparer<T>
public class ComparisonComparer<T> : IComparer<T>, IComparer
{
    private readonly Comparison<T> _comparison;

    public ComparisonComparer(Comparison<T> comparison)
    {
        _comparison = comparison;
    }

    public int Compare(T x, T y)
    {
        return _comparison(x, y);
    }

    public int Compare(object o1, object o2)
    {
        return _comparison((T)o1, (T)o2);
    }
}

With these extensions, sort your IList just like you would a List:

IList<string> iList = new []
{
    "Carlton", "Alison", "Bob", "Eric", "David"
};

// Use the custom extensions:

// Sort in-place, by string length
iList.Sort((s1, s2) => s1.Length.CompareTo(s2.Length));

// Or use OrderBy()
IEnumerable<string> ordered = iList.OrderBy((s1, s2) => s1.Length.CompareTo(s2.Length));

There's more info in the post: http://blog.velir.com/index.php/2011/02/17/ilistt-sorting-a-better-way/

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