Collection Synchronizer

CollectionSynchronizer.cs

public class CollectionSynchronizer<TSource, TDestination>
{
    public Action<TSource> Add { get; set; }
    public Action<TDestination> Remove { get; set; }
    public Action<TSource, TDestination> Update { get; set; }
    public Func<TSource, TDestination, bool> Compare { get; set; }

    /// <summary>
    /// Synchronize changes from source to destination collection.
    /// Source collection is not changed.
    /// </summary>
    public void Synchronize(ICollection<TSource> sourceItems, ICollection<TDestination> destinationItems)
    {
        RemoveItems(sourceItems, destinationItems);

        AddOrUpdateItems(sourceItems, destinationItems);
    }

    /// <summary>
    /// Remove items from destination collection.
    /// </summary>
    private void RemoveItems(ICollection<TSource> sourceCollection, ICollection<TDestination> destinationCollection)
    {
        foreach (var destinationItem in destinationCollection.ToArray())
        {
            var sourceItem = sourceCollection.FirstOrDefault(item => Compare(item, destinationItem));

            if (sourceItem == null)
            {
                Remove(destinationItem);
            }
        }
    }

    /// <summary>
    /// Add or update item in destination collection.
    /// </summary>
    /// <param name="sourceCollection"></param>
    /// <param name="destinationCollection"></param>
    private void AddOrUpdateItems(ICollection<TSource> sourceCollection, ICollection<TDestination> destinationCollection)
    {
        var destinationList = destinationCollection.ToList();

        foreach (var sourceItem in sourceCollection)
        {
            var destinationItem = destinationList.FirstOrDefault(item => Compare(sourceItem, item));

            if (destinationItem == null)
            {
                Add(sourceItem);
            }
            else
            {
                Update(sourceItem, destinationItem);
            }
        }
    }
}