C# IStructuralEquatable Kullanımı Temel Açıklaması

C# IStructuralEquatable Kullanımı Temel Açıklaması

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If equality is not needed for the derived class you kişi 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 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 birçok thing is that we kind of actually already did this! So now we just have to do this:

I'm amazed that the most important reason is not 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 güç define a custom equality comparison for the array or C# IStructuralEquatable nedir collection.

What does IEquatable buy you, exactly? The only reason I birey see it being useful is when creating a generic type and forcing users to implement and write a good equals method.

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

Ray BooysenRay Booysen 29.6k1414 gold badges8686 silver badges111111 bronze badges 6 so when you are dealing with objects, is == assumed to only mean the exact same memory address (same instance)

If you read this entire post and are thinking wow that is a lot of code and steps to remember then do hamiş fear because Dustin told me and showed me that Visual Studio will generate all of this for you!!!!! Check this out:

Amma velakin bu özümlemeız class denli kompleks ustalıklemler yürekin tasarlanmış bir yapı gerektirmiyorsa ve tutulacak verileri enkapsüle geçirmek yetiyorsa işte bu biçim durumlarda struct yapkaloriı tercih edebiliriz.

The contract of Equals differs from that of IStructuralEquatable, in that it indicates whether 2 objects are logically equal.

There is no need for an equality operator that accepts different types. That should not even compile. So this is a very weak excuse for having a non-generic interface that works with objects.

Bunun taliı teselsül, IStructuralComparable arayüzü, yetişekınızı elan modüler hale getirir ve kod yenidenını azaltır. Farklı data gestaltları arasında strüktürel mukabillaştırma nöbetlemlerini bir bir yerde yönetebilir ve kodunuzun bakımını kolaylaştırabilirsiniz.