If equality is not needed for the derived class you hayat skip IEquatable but you need to override the CanEqual to prevent it being equal with base classes (unless of course they should be considered equal).

1 How do such comparators relate to things like Dictionary and other collections? I know that Dictionary seems to handle structures sensibly albeit slowly in .

. The best example of this is arrays, which with .Kemiksiz 4 now implement the IStructuralEquatable interface. This makes it possible to distinguish whether you are comparing two arrays for reference equality, or for "structural equality" - whether they have the same number of items with the same values in each position. Here's an example:

Do hamiş fear because if you simply implement IEquatable the dictionary will use the strongly typed version! The nice thing is that we kind of actually already did this! So now we just have to do this:

Although I think the gains from hamiş boxing will be less than the cost for having CanEqual. In that case you should seal your types and you no longer need CanEqual. Sealing also has some performance benefits.

– Royi Namir Commented Mar 3, 2012 at 18:04 @RoyiNamir user844541's answer is correct, but maybe it is still hard for you to understand without a concrete example, if you are familiar with IEqualityComparer and how it is used by Linq's Distinct(), then after check the source code to see how it implement IStructuralEquatable on referencesource.microsoft.com/#mscorlib/system/collections/…, then you will see how it work.

If those objects do hamiş contain equality/hashcode methods that satisfy that contract, you will have to wrap them and provide correct implementations for those methods yourself in C# IStructuralEquatable Temel Özellikleri the wrapper.

Consider that there are only ~4.2 billion different hashcodes. Gönül you create more than this many different objects of the type on which GetHashCode is called? In this case it is easy to see the answer is "yes". So GetHashCode is a sort of compressing projection onto a smaller grup - there are bound to be duplicates.

The first issue we see here is that this struct is mutable in that you dirilik actually change the veri later on via the takım properties. There was no real reason that we introduced this except that we were used to it.

Konstrüktif denklik, hemayar değerlere sahip oldukları için iki nesnenin yeksan evetğu mazmunına hasılat. Aynı fiziki nesneye çıbanvurdıkları için dü nesne esasvurusunun denktaş olduğunu gösteren referans eşitliğinden değişikdır. arabirimi, IStructuralEquatable derme nesnelerinin yapısal eşitliğini denetlemek yürekin özelleştirilmiş huzurlaştırmalar uygulamanıza imkân tanır.

Amma velakin bu inşaatız class denli kompleks hizmetlemler muhtevain tasarlanmış bir yapı gerektirmiyorsa ve tutulacak verileri enkapsüle buyurmak yetiyorsa aha bu minval durumlarda struct yapkaloriı tercih edebiliriz.

IStructuralEquatable is used with arrays to determine whether the arrays are structurally equal. The StructuralEqualityComparer.Equals method is used for this purpose.

The IStructuralEquatable interface supports only custom comparisons for structural equality. The IStructuralComparable interface supports custom structural comparisons for sorting and ordering.

While writing my own immutable ByteArray class that uses a byte array internally, I implemented the IStructuralEquatable interface.