5 Basit Teknikleri için C# IStructuralEquatable nerelerde kullanılıyor

5 Basit Teknikleri için C# IStructuralEquatable nerelerde kullanılıyor

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Why do we have IStructuralComparable and IStructuralEquatable when there already exist the IComparable and IEquatable interfaces? The answer I would offer is that, in general, it's desirable to differentiate between reference comparisons and structural comparisons.

= to provide value equality checks (vs the default reference equality check). The MSDN documentation suggests you only do it for immutable types. There are also issues involving interfaces and operator overloading.

If you want to implement IEquatable in a class hierarchy you can use the following pattern. It prevents derived (including sibling) classes from being equal.

Does anyone know what happens if you do not implement iequtalable when using generic collections? 2

It is used by the third example bey an argument to the Equals(Object, IEqualityComparer) method of the IStructuralEquatable interface that tuples implement. It compares two Double or two Single values by using the equality operator. It passes values of any other type to the default equality comparer.

– Royi Namir Commented Mar 3, 2012 at 18:04 @RoyiNamir user844541's answer is correct, but maybe it is still hard for you to understand without a concrete example, if you are familiar with IEqualityComparer and how it is used by Linq's Distinct(), then after check the source code to see how it implement IStructuralEquatable on referencesource.microsoft.com/#mscorlib/system/collections/…, then you will see how it work.

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 derece 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 found that my two different arrays had the same structural hash code

Ray BooysenRay Booysen C# IStructuralEquatable nerelerde kullanılıyor 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 inşaatız class derece kompleks medarımaişetlemler yürekin tasarlanmış bir yapı gerektirmiyorsa ve tutulacak verileri enkapsüle kılmak yetiyorsa ahacık bu minval durumlarda struct yapkaloriı tercih edebiliriz.

IStructuralEquatable is used with arrays to determine whether the arrays are structurally equal. The StructuralEqualityComparer.Equals method is used for this purpose.

Default property. The second time, it passes the default equality comparer that is returned by the StructuralComparisons.StructuralEqualityComparer property. The third time, it passes the custom NanComparer object. As the output from the example shows, the first three method calls return true, whereas the fourth call returns false.

However, this is not so great if you are using the struct in a dictionary bey my good friend Dustin mentioned to me because a Dictionary will always use the object version of Equals, which falls back to boxing :(