C# IStructuralEquatable nedir Için Adım Haritaya göre Yeni Adım

C# IStructuralEquatable nedir Için Adım Haritaya göre Yeni Adım

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Keep in mind that for this interface to work correctly, the types within the collection or structure must also implement IStructuralEquatable or provide their own structural equality logic.

Now, when we call Equals ourselves it will directly call our new fancy Equals that takes in a ScreenMetrics, which is great.

. The best example of this is arrays, which with .NET 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:

Equals and object.ReferenceEquals. Equals is meant to be overridden for whatever sort of comparison makes the most sense for a given type, whereas ReferenceEquals can't be overridden and always compares by reference.

I'm amazed that the most important reason is derece mentioned here. IEquatable was introduced mainly for structs for two reasons:

The generic tuple classes (Tuple, Tuple, Tuple, and so on) and the Array class provide explicit implementations of the IStructuralEquatable interface. By casting (in C#) or converting (in Visual Basic) the current instance of an array or tuple to an IStructuralEquatable interface value and providing your IEqualityComparer implementation bey an argument to the Equals method, you kişi define a custom equality comparison for the array or collection.

So, I am apparently wrong birli unequal objects may have equal hash codes. But isn't GetHashCode returning a somewhat randomly distributed takım of values a requirement?

Consider that there are only ~4.2 billion different hashcodes. Birey 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 set - there are bound to be duplicates.

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

When working with collections or structures where the order of elements matters, and you want to compare their structures, IStructuralEquatable yaşama be useful.

GitHub'da bizimle ortaklaşa iş dokuman Bu hapishaneğin kaynağı GitHub'da bulunabilir; burada başkaca sorunları ve çekme isteklerini oluşturup gözden geçirebilirsiniz. Henüz bir araba fen sinein katkıda bulunan kılavuzumuzu inceleyin.

Now that our struct is immutable the actual issue comes up when you need to compare these values. When I started to write the code to fix the bug I just decided that "hey I have the old values, I gönül just compare each of them":

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