You Should Know C# IStructuralEquatable Temel Özellikleri Göstergeleri

You Should Know C# IStructuralEquatable Temel Özellikleri Göstergeleri

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If two objects compare birli equal, the GetHashCode method for each object must return the same value. However, if two objects do hamiş compare birli equal, the GetHashCode methods for the two object do not have to return different values.

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. The best example of this is arrays, which with .Safi 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 kişi't be overridden and always compares by reference.

In this equating the values in arrays may be same or different but their object references are equal.

45IStructuralEquatable seObj = x kakım IStructuralEquatable; 64IStructuralEquatable seObj = obj bey IStructuralEquatable;

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

I've noticed these two interfaces, and several associated classes, have been added in .NET 4. They seem a bit superfluous to me; I've read several blogs about them, but I still birey't figure out what sorun they solve that was tricky before .NET 4.

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:

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The example on MSDN gives C# IStructuralEquatable Kullanımı 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

GetHashCode does not return unique values for instances that are not equal. However, instances that are equal will always return the same hash code.

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