Cool ObservableCollection Sort Extension

[Garry]

I came across the need to be able to sort my ObservableCollections the other day and I found a nice code snippet demonstrating how to sort an ObservableCollection even if the collection type does not support IComparable. I added the ReverseCompare/Descending sort just in case. Anyhow thought it was a neat piece of code and hope it may help some others out there.

Enjoy!

public static class CollectionSorter
    {
        public static void Sort<T>(this ObservableCollection<T> collection, Comparison<T> comparison)
        {
            var comparer = new Comparer<T>(comparison);

            List<T> sorted = collection.OrderBy(x => x, comparer).ToList();

            for (int i = 0; i < sorted.Count(); i++)
                collection.Move(collection.IndexOf(sorted[i]), i);
        }

        public static void DescendingSort<T>(this ObservableCollection<T> collection, Comparison<T> comparison)
        {
            var comparer = new ReverseComparer<T>(comparison);

            List<T> sorted = collection.OrderBy(x => x, comparer).ToList();

            for (int i = 0; i < sorted.Count(); i++)
                collection.Move(collection.IndexOf(sorted[i]), i);
        }
    }

    internal class Comparer<T> : IComparer<T>
    {
        private readonly Comparison<T> comparison;

        public Comparer(Comparison<T> comparison)
        {
            this.comparison = comparison;
        }

        #region IComparer<T> Members

        public int Compare(T x, T y)
        {
            return comparison.Invoke(x, y);
        }

        #endregion
    }

    internal class ReverseComparer<T> : IComparer<T>
    {
        private readonly Comparison<T> comparison;

        public ReverseComparer(Comparison<T> comparison)
        {
            this.comparison = comparison;
        }

        #region IComparer<T> Members

        public int Compare(T x, T y)
        {
            return -comparison.Invoke(x, y);
        }

        #endregion
    }

then you can use it on your ObservableCollections as such. 

private void Log(LogEntry log)
        {
            LoggedEvents.Add(log);
            LoggedEvents.DescendingSort((x, y) => x.TimeStampString.CompareTo(y.TimeStampString));
        }

        private ObservableCollection<LogEntry> entries = new ObservableCollection<LogEntry>();
        public ObservableCollection<LogEntry> LoggedEvents
        {
            get
            {
                return entries;
            }
            set
            {
                entries = value;
                RaisePropertyChanged(LoggedProperty);
            }
        }

[Jonas]

The orderby-operation is fast, but since you do an indexof for each item in the list, the extension-method will have Ordo(n2) which is a bad thing... the collection should be ordered in place with a quicksort to keep performance good when working with large lists.