En Kuralları Of C# IStructuralEquatable Kullanımı

En Kuralları Of C# IStructuralEquatable Kullanımı

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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?

= 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.

Reference types (read classes) don't benefit birli much. The IEquatable implementation does let you avoid a cast from System.Object but that's a very trivial gain. I still like IEquatable to be implemented for my classes since it logically makes the intent explicit.

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. Kakım the output from the example shows, the first three method calls return true, whereas the fourth call returns false.

Let us derece forget about additional operators and hamiş just relying on Equals. We sevimli implement the == and != operators easily:

Your concern is that Object.GetHashCode() does hamiş provide values that are stable and the concern is very valid birli dirilik be seen in the first box headed by Caution in the documentation:

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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

The reason why you need the IStructuralEquatable is for defining a new way of comparision that would C# IStructuralEquatable Kullanımı be right for all the objects .

In Xamarin.Essentials we use the C# struct all over the place to encapsulate "small groups of related variables" for our event handlers. They are groups of veri that don't need to be created by the developers consuming the veri and are only really used for reading the data.

Each of your objects should use a hashcode based on the contents of the object. If you have a value type containing 3 ints, use those when computing the hash code. Like this, all objects with identical content will have the same hash code, independent of app domain and other circumstances.

Tamam, makalede eksiklikler olabilir. Bunu tenkit olarak kabul ediyorum. Işlevsel programlamada struct kullanılmasının nedenini de bilmiyor, başarım ve özge konular karşı da herhangi bir fikir barındırmıversiyon. Siz biliyorsanız lütfen aydınlatır mısınız?

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 :(