En iyi Tarafı C# IStructuralEquatable Nasıl kullanılır

En iyi Tarafı C# IStructuralEquatable Nasıl kullanılır

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It's normally expected that if you implement IEquatable.Equals you will also override Object.Equals to be consistent. In this case how would you support both reference and structural equality?

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:

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 güç't be overridden and always compares by reference.

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comparer IEqualityComparer An object that determines whether the current instance and other are equal.

The IStructuralEquatable interface enables you to implement customized comparisons to check for the structural equality of collection objects. This is also made clear by the fact that this interface resides in the System.Collections namespace.

When an implementer overrides the virtual Equals method in a struct, the purpose is to provide a more efficient means of performing the value equality check and optionally to base the comparison on some subset of the struct's field or properties.

Reading through the excellent blog post by Sergey on struct equality performance he mentions that the default implementations are pretty slow and using boxing for each member. Additionally, he mentions that a memory comparison may derece give you the correct results in this super simple example:

Yapısal müsavat, müsavi değerlere malik oldukları kucakin iki nesnenin denktaş evetğu mazmunına gelir. Aynı fiziki nesneye saksıvurdıkları derunin dü nesne mebdevurusunun yeksan olduğunu gösteren müracaat eşitliğinden değişikdır. arabirimi, IStructuralEquatable koleksiyon nesnelerinin yapısal eşitliğini denetlemek yürekin özelleştirilmiş muhaliflaştırmalar uygulamanıza imkân teşhisr.

This member is an explicit interface member implementation. It C# IStructuralEquatable nedir güç be used only when the Array instance is cast to an IStructuralEquatable interface.

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 emanet just compare each of them":

There is no need for an equality operator that accepts different types. That should hamiş even compile. So this is a very weak excuse for having a non-generic interface that works with objects.

Specifically, I do derece know the exact type of the object. The only assumption I make is that it inherit from IStructuralEquatable.