Greatest Kılavuzu C# IStructuralEquatable Kullanımı için

Greatest Kılavuzu C# IStructuralEquatable Kullanımı için

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That is, you dirilik create your own definition of structural equality and specify that this definition be used with a collection type that accepts the IStructuralEquatable interface.

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

The following example creates two identical 3-tuple objects whose components consist of three Double values. The value of the second component is Double.NaN. The example then calls the Tuple.Equals method, and it calls the IStructuralEquatable.Equals method three times. The first time, it passes the default equality comparer that is returned by the EqualityComparer.

Do not 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 katışıksız some performance benefits.

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 as an argument to the Equals method, you hayat define a custom equality comparison for the array or collection.

1 My understanding is that it's used for collection like types, and encapsulates the structural part of the comparison, but leaved the comparison of the elements to a comparer passed in by the user. But I'm not really sure if I really got it.

In my implementation I delegated the task of calculating hash codes to the internal array. While testing it, to my great surprise, I C# IStructuralEquatable Kullanımı found that my two different arrays had the same structural hash code

comparer IEqualityComparer İki nesnenin müsavi olup olmadığını değerlendirmek yürekin kullanılacak yöntemi tanımlayan nesne.

Bir önceki hizmetlemin aynısını AsOrdered extensionı ile dokumaldığında işlem tekrar koşut olarak dokumalır, fakat skorlar sıralı evet.

Ancak, fruits1 ve fruits3 dizileri aynı elemanlara farklı sıralarda iye evetğundan, CompareTo metodu farklı bir kırat döndürür ve bu dizilerin konstrüktif olarak müsavi olmadığını belirtir.

The example on MSDN gives part of the answer here; it seems to be useful for heterogeneous equality, rather than homogeneous equality - i.e. for testing whether two objects (/values) of potentially different types

Just look at the default ValueType.Equals(object) code that gets called otherwise. It's an absolute performance killer that introduces boxing, type evaluation and finally falls back on reflection if any of the fields are reference types.

The Equals method supports custom structural comparison of array and tuple objects. This method in turn calls the comparer object's IEqualityComparer.Equals method to compare individual array elements or tuple components, starting with the first element or component.