Anonymous IComparer implementation
Is it possible to define an anonymous implementation of IComparer?
I believe Java allows anonymous classes to be defined inline - does C#?
Looking at this code I want to define a custom IComparer
inline
public static IOrderedEnumerable<TSource> OrderBy<TSource, TKey>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector,
IComparer<TKey> comparer
)
As indicated in one of the comments below, .Net 4.5 allows this via a static method on the Comparer<> class, e.g. comparing two objects based on the value of a property in the class:
var comparer = Comparer<KilowattSnapshot>.Create(
(k1, k2) => k1.Kilowatt.CompareTo(k2.Kilowatt) );
Obviously this can be used inline rather than assigned to a variable.
Even though you can't create anonymous classes that implement interfaces, you can usually use the Comparison Delegate instead of the IComparer Interface in most cases (like sorting, etc.):
Array.Sort(arr, (x, y) => 1);
Also there are some built-in implementations of IComparer
like the Comparer Class or the StringComparer Class...
The .NET framework version 4.5 provides the method Comparer.Create(Comparison) to create comparers based on a specified comparison delegate (which can be a lambda function). However people who are working with earlier versions of .NET will probably need to implement something similar themselves.